11 research outputs found

    Enhancing Jc(B,theta) in YBa2Cu3O7-delta via nano-engineering of pinning structures

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    Critical current density (Jc) has been identified as one of the most critical parameters for the practical application of high temperature superconductors such as YBa2Cu3O7-ÎŽ (YBCO). Unfortunately, the Jc of optimized un-doped YBCO films barely satisfies the criteria for these applications. High JÂŹc can be achieved by introducing strong artificial pinning centers in YBCO which can inhibit flux motion and prevent dissipation. However, insertion of strong pins has been observed to strain and poison the YBCO lattice resulting in unnecessary degradation of Tc and low field Jc. In this work, two types of strong pinning centers with negligible effect on the Tc and low field Jc were incorporated in YBCO films via strain engineering on the nanoscale. The nanotube pores were generated by depositing YBCO films on vicinal SrTiO3 (STO) substrates. A close correlation between Jc and the magnetic pinning potential Up of the nanotube pores has been demonstrated below the accommodation field, suggesting that nanotube pores are strong pins on the magnetic vortices. Splayed BaZrO3 nanorords (BZO-NRs) were generated in YBCO film by depositing 2 vol.% BZO-doped YBCO on vicinal STO substrates. The interplay between the lattice strain caused by the large lattice mismatch between YBCO and BZO and the anisotropic strain due to vicinal growth resulted in the dispersed orientation of BZO-NRs. The splayed BZO-NRs led to an enhanced Jc in the entire range of the magnetic field orientation up to 5 T as compared to the non-splayed case of YBCO/BZO-NRs films

    The challenges of fighting sex trafficking in the legalized prostitution market of the Netherlands

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    In 2000, the Dutch authorities lifted the ban on brothels in the Netherlands. The essence of their approach was to regulate prostitution. People of legal age could now voluntarily sell and purchase sexual services. Brothels which complied with certain licensing conditions were legalized. This paper critically assesses the logic of a position that argues that human trafficking is reduced when actors in the legalized prostitution sector are made responsible for what happens on their premises (using licensing conditions). This idea is confronted with empirical evidence about the Netherlands in general and the city of Amsterdam in particular. Furthermore, the paper addresses two questions. What are consequences of the regularization of prostitution for the criminal investigation and prosecution of sex trafficking? How do criminal justice agencies collaborate with regulatory authorities in the regulated and non-regulated sectors of the prostitution market? The main conclusion is that the screening of brothel owners and the monitoring of the compliance of licensing conditions do not create levels of transparency that enable sex trafficking to be exposed. The prostitution business retains many characteristics of an illegitimate market and the legalization and regulation of the prostitution sector has not driven out organized crime. On the contrary, fighting sex trafficking using the criminal justice system may even be harder in the legalized prostitution sector. © 2014 Springer Science+Business Media Dordrecht
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