For a proper characterization of multi-filamentary NbTi and Nb 3 Sn strands and a better understanding of their performance in short sample tests, as well as for increased understanding of inter-strand current redistribution in cabled conductors, a quantitative knowledge of the inter-filament transverse resistance is essential. In particular, in the case of strain or crack distributions among and along filaments in strain-sensitive superconductors such as Nb 3 Sn cable-in-conduit conductors, a much better understanding of the voltage-current transition is required as a basis for the analysis of full-size cables.Two particular four-probe voltage-current methods are developed to measure the transverse inter-filament resistance distribution directly, both in well-established and in state-of-the-art superconductors that are presently applied in the ITER, JT-60SA and LHC magnets. To extract values of the filament-to-matrix contact resistance from these direct experiments, some further assumptions are needed. These assumptions are based on FEM simulations and on measurement of the longitudinal strand resistance.An overview is given of a wide range of measurements on various NbTi and Nb 3 Sn strands, performed at temperatures below 10 K and at various applied magnetic fields. We present the results of the experiments and simulations and demonstrate how the extracted characteristic parameters provide a better insight into the current flow patterns within the strands.

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Mammalian oocytes such as mouse oocytes have a highly elastic outer membrane, zona pellucida (ZP) that cannot be penetrated without significantly deforming the oocyte, even with a sharp micropipette. Piezo drill devices leverage lateral and axial vibration of the micropipette to accomplish ZP penetration with greatly reduced oocyte deformation. However, existing piezo drills all rely on a large lateral micropipette vibration amplitude ( 20 ) and a small axial vibration amplitude (0.1 ). The very large lateral vibration amplitude has been deemed to be necessary for ZP penetration although it also induces larger oocyte deformation and more oocyte damage. This paper reports on a new piezo drill device that uses a flexure guidance mechanism and a systematically designed pulse train with an appropriate base frequency. Both simulation and experimental results demonstrate that a small lateral vibration amplitude (e.g., 2 ) and an axial vibration amplitude as large as 1.2 were achieved. Besides achieving 100% effectiveness in the penetration of mouse oocytes (n = 45), the new piezo device during ZP penetration induced a small oocyte deformation of 3.4 versus larger than 10 using existing piezo drill devices.

Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and automatic detection. The applications of digital image processing in pavement crack detection, distresses classification and evaluation were reviewed in the paper. The key problems were analyzed, such as image enhancement, image segmentation and edge detection. The experiment results of the commonly used algorithms forcefully supported following conclusion: the noise in pavement crack images is effectively removed by median filtering, the histogram modification technique is a useable segmentation approach, the canny edge detection is an ideal identification approach of pavement distresses.

A ReBCO coated conductor maintains high current-carrying capability under a high magnetic field and superior mechanical performance. As a promising candidate material for high-field high-temperature superconductor magnets, it has been designed for application in the China Fusion Engineering Test Reactor CS coil, with a maximum magnetic field requirement higher than 17 T. In practical application of the ReBCO tapes, the characteristic I c response with respect to electromagnetic (EM) and thermal stress is important for safe operation of the magnet. In this paper, a nine-turn solenoid magnet was wound from 4 m of CORC cable and tested at 4.2 K in a background magnetic field of up to 19 T. The aim is to check the stability of the current-carrying properties of the ReBCO cable under combined thermal and EM loads. The solenoid coil results in a combined peak magnetic field on the conductor of 19.4 T at a critical current of 888 A. Furthermore, no performance degradation was observed after 20 cycles of operation at 800 A (90% I c ) under a background field of 19 T and 10 cycles of warm-up-cool-down between 77 K and room temperature. This demonstrates the stable performance of ReBCO conductors for high-field magnet application with EM and thermal cycles.