Self Field Measurements by Hall Sensors on the SeCRETS Long Sample CICCs in SULTAN

The aim of this work is to determine the existence and degree of the current unbalance of two types of cable-in-conduit conductors (CICC) of the SeCRETS long sample experiment, and its influence on the conductors' performance. The self-field measurements are performed by using six sets of annular Hall sensors, each containing six sensors, and two linear arrays with ten sensors. The change of the self-field is associated with the redistribution of the transport current between the strands inside the conductor during and after a ramp of current, due to changes of the applied magnetic field or temperature of the conductor. During the DC, AC losses and stability tests, the signals from the Hall sensors were recorded. In DC tests, a clear change of the self-field pattern is observed in the high field region when either current or temperature approached their critical (I/sub cs/ and T/sub cs/) values. No change in the self-field pattern is observed in the experiments with pulsed fields. The method requires improvements for a reasonable quantitative assessment of the current unbalance in the conductor

Self field measurements by Hall sensors on the SeCRETS short sample CICC's subjected to cyclic load

An imbalance in the transport current among the strands of a Cable-in-Conduit conductors (CICC) can be associated with the change of their performance. In order to understand and improve the performance of CICC's, it is essential to study the current imbalance. This paper focuses on the study of the current imbalance in two short samples of the SeCRETS (Segregated Copper Ratio Experiment on Transient Stability) conductors subjected to a cyclic load in the SULTAN facility. The self field around the conductors was measured on four locations by 32 miniature Hall sensors for a reconstruction of the current distribution. The results of the self field measurements in the DC tests are presented and discussed

Transient Stability Analysis of the SeCRETS Experiment in SULTAN

We present here the results of the analysis of the stability experiment SeCRETS, performed on two Nb$_{3}$Sn cable-in-conduit conductors with the same amount of total copper stabilizer, but different degree of segregation. The model used for the analysis, including superconducting strands, conductor jacket and helium, is solved with the code GandalfTM. We obtain a qualitative agreement of simulation results and experimental values. The simulation results confirm that in the operation regime explored in the experiment the segregated copper is not effective for stability. The details of the current sharing and the approximation taken for the transient heat transfer are shown to be critical for the interpretation

Re-Design of a Packaging Machine Employing Linear Servomotors: a Description of Modelling Methods and Engineering Tools

open4noPosition-controlled servo-systems mostly make use of electric rotary motors and gearboxes and, if necessary, a transmission mechanism to convert rotary into linear motion. Even so, especially in the field of automatic machines for packaging, it should be highlighted that most of the required movements are usually linear, so that Linear Electric Motors (LEM) should somehow represent a more convenient solution for designers. LEM can directly generate the required trajectory avoiding any intermediate mechanism, thus potentially minimizing the number of linkages/mechanical parts and, therefore, the undesired backlash and compliance that come along. On the other hand, particularly within small-medium enterprises, LEM may be rarely employed despite obvious advantages, mostly due to their high-cost as compared to rotary actuators and the lack of knowledge of the achievable performance. In light of these considerations, the present paper reports an industrial case study where an automatic machine for packaging, comprising distributed actuation and several tasks requiring a linear motion, has been completely redesigned employing different kind of LEM (i.e. iron-core and iron-less). Such machine architecture is compared to a “traditional” design where brushless gear-motors are coupled to linkage systems. The paper mainly focuses on the selection criteria for the LEM system and on the engineering tools employed during the different design stages. Qualitative and quantitative conclusions are finally drawn, which may provide useful hints for designers that are willing to actually employ LEM-based solutions in an industrial scenarioopenBerselli, Giovanni; Bilancia, Pietro; Bruzzone, Luca; Fanghella, PietroBerselli, Giovanni; Bilancia, Pietro; Bruzzone, Luca; Fanghella, Pietr

Application of the Code THEA to the CONDOPT Experiment in SULTAN

The CONDOPT (CONDuctor OPTimization) experiment has been recently completed in SULTAN. The current sharing behaviour of Nb$_{3}$Sn samples was assessed as a function of the number of cyclic loads experienced during current sweeps in a 10 T background field. We present here results of a computer analysis performed with the code THEATM (for consistent Thermal, Hydraulic and Electric Analysis) in support of the interpretation of the experimental results. We focus in particular on the critical current and current sharing temperature runs, providing details on the features and effects of current distribution among cable sub-stages

Class II ADP-ribosylation factors are required for efficient secretion of Dengue viruses

This article is available open access through the publisher’s website.Identification and characterization of virus-host interactions are very important steps toward a better understanding of the molecular mechanisms responsible for disease progression and pathogenesis. To date, very few cellular factors involved in the life cycle of flaviviruses, which are important human pathogens, have been described. In this study, we demonstrate a crucial role for class II Arf proteins (Arf4 and Arf5) in the dengue flavivirus life cycle. We show that simultaneous depletion of Arf4 and Arf5 blocks recombinant subviral particle secretion for all four dengue serotypes. Immunostaining analysis suggests that class II Arf proteins are required at an early pre-Golgi step for dengue virus secretion. Using a horseradish peroxidase protein fused to a signal peptide, we show that class II Arfs act specifically on dengue virus secretion without altering the secretion of proteins through the constitutive secretory pathway. Co-immunoprecipitation data demonstrate that the dengue prM glycoprotein interacts with class II Arf proteins but not through its C-terminal VXPX motif. Finally, experiments performed with replication-competent dengue and yellow fever viruses demonstrate that the depletion of class II Arfs inhibits virus secretion, thus confirming their implication in the virus life cycle, although data obtained with West Nile virus pointed out the differences in virus-host interactions among flaviviruses. Our findings shed new light on a molecular mechanism used by dengue viruses during the late stages of the life cycle and demonstrate a novel function for class II Arf proteins.Research Fund for Control of Infectious Diseases of Hong Kong and BNP Paribas Corporate and Investment Banking