Acoustic detection in superconducting magnets for performance characterization and diagnostics

Quench diagnostics in superconducting accelerator magnets is essential for understanding performance limitations and improving magnet design. Applicability of the conventional quench diagnostics methods such as voltage taps or quench antennas is limited for long magnets or complex winding geometries, and alternative approaches are desirable. Here, we discuss acoustic sensing technique for detecting mechanical vibrations in superconducting magnets. Using LARP high-field Nb3Sn quadrupole HQ01 [1], we show how acoustic data is connected with voltage instabilities measured simultaneously in the magnet windings during provoked extractions and current ramps to quench. Instrumentation and data analysis techniques for acoustic sensing are reviewed.Comment: 5 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet, Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva, Switzerlan

Introduction to the Issue

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Alexander Nikolayevich Radishchev and Destiny of Russian Enlightenment

The main framework of the present paper is constituted by the problematics of the Russian Enlightenment in its characteristic features and tendencies of its formation. The author expounds Enlightenment as an intellectual symbol representing the Western thought in Russian environment not only of the 18th century. Enlightenment as a period in the history of Russian philosophical thinking is fundamentally determined by the reign of Empress Catherine II. Her enlightening and reactive attitudes following from the events of 1789 are the subject of the author’s interest. To illustrate the turbulent changes in Russian intellectual milieu after the French Revolution, the author uses an example of A. N. Radishchev who, in the spirit of Enlightenment, published his A Journey from St. Petersburg to Moscow in 1790. The author also describes the impact of publishing this work on Radishchev himself as well as its influence on the later period in the form of strong interpretative tradition.The main framework of the present paper is constituted by the problematics of the Russian Enlightenment in its characteristic features and tendencies of its formation. The author expounds Enlightenment as an intellectual symbol representing the Western thought in Russian environment not only of the 18th century. Enlightenment as a period in the history of Russian philosophical thinking is fundamentally determined by the reign of Empress Catherine II. Her enlightening and reactive attitudes following from the events of 1789 are the subject of the author’s interest. To illustrate the turbulent changes in Russian intellectual milieu after the French Revolution, the author uses an example of A. N. Radishchev who, in the spirit of Enlightenment, published his A Journey from St. Petersburg to Moscow in 1790. The author also describes the impact of publishing this work on Radishchev himself as well as its influence on the later period in the form of strong interpretative tradition

Book Reviews

Reviews of The Right to Stay Home: How U.S. Policy Drives Mexican Migration and Culling the Masses: The Democratic Origins of Racist Immigration Policy in the America

Acoustic thermometry for detecting quenches in superconducting coils and conductor stacks

Quench detection capability is essential for reliable operation and protection of superconducting magnets, coils, cables, and machinery. We propose a quench detection technique based on sensing local temperature variations in the bulk of a superconducting winding by monitoring its transient acoustic response. Our approach is primarily aimed at coils and devices built with high-temperature superconductor materials where quench detection using standard voltage-based techniques may be inefficient due to the slow velocity of quench propagation. The acoustic sensing technique is non-invasive, fast, and capable of detecting temperature variations of less than 1 K in the interior of the superconductor cable stack in a 77 K cryogenic environment. We show results of finite element modeling and experiments conducted on a model superconductor stack demonstrating viability of the technique for practical quench detection, discuss sensitivity limits of the technique, and its various applications

An Improved Method for Obtaining Small Pressed Powder Pellets for the Analysis by XRF

A rapid, very low cost of instrumentation and simple approach to specimen preparation for the analysis by X-ray fluorescence spectrometry is presented. This technique requires a few mg of powdered samples, which are compressed to produce pellets. This procedure is employed for determining major, minor and trace elements in muscovites and K-feldspars. Factors affecting measured intensities, such as particle size and distribution, surface texture, pelletizing pressure, etc, are considered. A description of the new sample preparation device, including technical characteristics, is also given. It is demonstrated that suitable specimen presentation to the X-ray beam is obtained by using our procedure.Fil: D`angelo, José Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Strasser, Edgardo. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Marchevsky, Eduardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Perino, Ernesto. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentin

Design of Boolean LUM Smoothers through Permutation Coloring Concept

Rank-order based LUM (lower-upper-middle) smoothers distinguishes by wide range of smoothing characteristics given by filter parameter. Thus, for the capability to achieve the best balance between noise suppression and signal details preservation, the LUM smoothers are preferred in smoothing applications. Thanks to threshold decomposition and stacking properties, the LUM smoothers belong to the class of stack filters. This paper is focused to the derivation of minimal positive Boolean function for LUM smoothers through permutation groups and a coloring concept

Dropped From the Rolls: Mexican Immigrants, Race, and Rights in the Era of Welfare Reform

Welfare reform transferred considerable discretion over eligibility standards and benefits to individual caseworkers, contributing to a highly diffuse, yet system-wide, practice of discrimination against nonwhite and foreign-born families within the new TANF program. Based on a two-year ethnographic study of welfare reform\u27s impact on Mexican immigrants in Los Angeles County, this article documents a pattern of heightened anti-immigrant sentiment and disentitlement within L.A. County\u27s welfare system following the passage of PRWORA. The vast majority of eligible immigrant families in our study lost some or all of their cash and food stamp benefits, and were systematically denied access to the work and social supports promised under welfare reform, including childcare, training and education, and transportation. Our research illuminates how race, gender, and immigrant status intersect to block Latinas\u27 access to welfare entitlements, and to maintain their position in low-wage and unstable employment. We describe the racial effects of three tactics used by welfare officials in L.A.: unlawful reductions or termination of immigrant benefits; harassment and humiliation through Job Club; and the tracking of immigrants away from education and into low-wage jobs. Placing the current welfare debate in the context of postcivil rights politics, we also question the refusal of mainstream policymakers and welfare researchers to engage issues of racial discrimination and inequality in their evaluation of PRWORA