Effect of high temperature heat treatments on the quality factor of a large-grain superconducting radio-frequency niobium cavity

Large-grain Nb has become a viable alternative to fine-grain Nb for the fabrication of superconducting radio-frequency cavities. In this contribution we report the results from a heat treatment study of a large-grain 1.5 GHz single-cell cavity made of "medium purity" Nb. The baseline surface preparation prior to heat treatment consisted of standard buffered chemical polishing. The heat treatment in the range 800 - 1400 C was done in a newly designed vacuum induction furnace. Q0 values of the order of 2x1010 at 2.0 K and peak surface magnetic field (Bp) of 90 mT were achieved reproducibly. A Q0-value of (5+-1)1010 at 2.0 K and Bp = 90 mT was obtained after heat treatment at 1400 C. This is the highest value ever reported at this temperature, frequency and field. Samples heat treated with the cavity at 1400 C were analyzed by secondary ion mass spectrometry, secondary electron microscopy, energy dispersive X-ray, point contact tunneling and X-ray diffraction and revealed a complex surface composition which includes titanium oxide, increased carbon and nitrogen content but reduced hydrogen concentration compared to a non heat-treated sample

The Quantum Socket: Three-Dimensional Wiring for Extensible Quantum Computing

Quantum computing architectures are on the verge of scalability, a key requirement for the implementation of a universal quantum computer. The next stage in this quest is the realization of quantum error correction codes, which will mitigate the impact of faulty quantum information on a quantum computer. Architectures with ten or more quantum bits (qubits) have been realized using trapped ions and superconducting circuits. While these implementations are potentially scalable, true scalability will require systems engineering to combine quantum and classical hardware. One technology demanding imminent efforts is the realization of a suitable wiring method for the control and measurement of a large number of qubits. In this work, we introduce an interconnect solution for solid-state qubits: The quantum socket. The quantum socket fully exploits the third dimension to connect classical electronics to qubits with higher density and better performance than two-dimensional methods based on wire bonding. The quantum socket is based on spring-mounted micro wires the three-dimensional wires that push directly on a micro-fabricated chip, making electrical contact. A small wire cross section (~1 mmm), nearly non-magnetic components, and functionality at low temperatures make the quantum socket ideal to operate solid-state qubits. The wires have a coaxial geometry and operate over a frequency range from DC to 8 GHz, with a contact resistance of ~150 mohm, an impedance mismatch of ~10 ohm, and minimal crosstalk. As a proof of principle, we fabricated and used a quantum socket to measure superconducting resonators at a temperature of ~10 mK.Comment: Main: 31 pages, 19 figs., 8 tables, 8 apps.; suppl.: 4 pages, 5 figs. (HiRes figs. and movies on request). Submitte

Yields and Sward Characteristics of Timothy Cultivars under Grazing

Seven timothy (Phleum pratense L.) cultivars were evaluated over three pasture seasons under rotational grazing to 7 or 11 cm post-grazing heights and regrowth periods of four to seven weeks. There was a trend for the pasture type timothy cultivars to outyield Champ timothy (check). Dry matter yields were lower for the 7 cm than 11 cm post-grazing height. Although the overall cultivar x post-grazing height interaction was not significant (P \u3e 0.05), there was variability in grazing tolerance among timothy cultivars. Yield of Kahu was maintained and vegetative tiller density of Kahu increased over the experimental period under 7 cm grazing. Proportion of vegetative tillers among the cultivars ranged from 0.20 to 0.61 in the primary growth but this proportion increased to 0.95 in the fourth grazing

Rehabilitating antisocial personalities: treatment through self-governance strategies

Offenders with antisocial personality disorder (ASPD) are widely assumed to reject psychotherapeutic intervention. Some commentators, therefore, argue that those with the disorder are better managed in the criminal justice system, where, following the introduction of indeterminate sentences, engagement with psychological treatment is coercively linked to the achievement of parole. By comparison, National Institute of Clinical Excellence guidelines on the management and treatment of ASPD recommend that those who are treatment seeking should be considered for admission to specialist psychiatric hospitals. The rationale is that prison-based interventions are underresourced, and the treatment of ASPD is underprioritised. The justification is that offenders with ASPD can be rehabilitated, if they are motivated. One problem, however, is that little is known about why offenders with ASPD seek treatment or what effect subsequent treatment has on their self-understanding. The aim of this paper is to address these unresolved issues. It draws on the findings of Economic and Social Research Council (ESRC) funded qualitative study examining the experiences of sentenced male offenders admitted to a specialist personality disorder ward within the medium secure estate and the medical practitioners who treat them. The data are analysed with reference to Michel Foucault’s work on governmentality and strategy in power relations. Two arguments are advanced: first, offenders with ASPD are motivated by legal coercive pressures to implement a variety of Foucauldian-type strategies to give the false impression of treatment progress. Second, and related, treatment does not result in changes in self-understanding in the resistive client with ASPD. This presupposes that, in respect of this group at least, Foucault was mistaken in his claim that resistive behaviours merely mask the effectiveness of treatment norms over time. Nevertheless, the paper concludes that specialist treatment in the hospital setting can effect changes in the resistive offender’s self-understanding, but not if the completion of treatment results, as is commonplace, in his prison readmission

Nitric Oxide PLIF Measurements in the Hypersonic Materials Environmental Test System (HYMETS)

Planar laser-induced fluorescence (PLIF) of naturally occurring nitric oxide (NO) has been used to obtain instantaneous flow visualization images, and to make both radial and axial velocity measurements in the HYMETS (Hypersonic Materials Environmental Test System) 400 kW arc-heated wind tunnel at NASA Langley Research Center. This represents the first application of NO PLIF flow visualization in HYMETS. Results are presented at selected facility run conditions, including some in a simulated Earth atmosphere (75% nitrogen, 20% oxygen, 5% argon) and others in a simulated Martian atmosphere (71% carbon dioxide, 24% nitrogen, 5% argon), for specific bulk enthalpies ranging from 6.5 MJ/kg to 18.4 MJ/kg. Flow visualization images reveal the presence of large scale unsteady flow structures, and indicate nitric oxide fluorescence signal over more than 70% of the core flow for specific bulk enthalpies below about 11 MJ/kg, but over less than 10% of the core flow for specific bulk enthalpies above about 16 MJ/kg. Axial velocimetry was performed using molecular tagging velocimetry (MTV). Axial velocities of about 3 km/s were measured along the centerline. Radial velocimetry was performed by scanning the wavelength of the narrowband laser and analyzing the resulting Doppler shift. Radial velocities of +/- 0.5 km/s were measured

Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits

We give a criterion for a Dynkin diagram, equivalently a generalized Cartan matrix, to be symmetrizable. This criterion is easily checked on the Dynkin diagram. We obtain a simple proof that the maximal rank of a Dynkin diagram of compact hyperbolic type is 5, while the maximal rank of a symmetrizable Dynkin diagram of compact hyperbolic type is 4. Building on earlier classification results of Kac, Kobayashi-Morita, Li and Sa\c{c}lio\~{g}lu, we present the 238 hyperbolic Dynkin diagrams in ranks 3-10, 142 of which are symmetrizable. For each symmetrizable hyperbolic generalized Cartan matrix, we give a symmetrization and hence the distinct lengths of real roots in the corresponding root system. For each such hyperbolic root system we determine the disjoint orbits of the action of the Weyl group on real roots. It follows that the maximal number of disjoint Weyl group orbits on real roots in a hyperbolic root system is 4.Comment: J. Phys. A: Math. Theor (to appear

Trends in, and predictors of, anxiety and specific worries following colposcopy: a 12-month longitudinal study

Objective Little is known about which women are at greatest risk of adverse psychological after-effects following colposcopy. This study examined time trends in, and identified predictors of, anxiety and specific worries over 12 months. Methods Women attending two hospital-based colposcopy clinics for abnormal cervical cytology were invited to complete psychosocial questionnaires at 4, 8 and 12 months following colposcopy. General anxiety and screening-specific worries (about cervical cancer, having sex and future fertility) were measured. Generalised estimating equations were used to assess associations between socio-demographic, lifestyle and clinical variables and risk of psychological outcomes. Results Of 584 women initially recruited, 429, 343 and 303 completed questionnaires at 4, 8 and 12 months, respectively. Screening-specific worries declined significantly over time but were still relatively high at 12 months: 23%, 39% and 18% for worries about cervical cancer, fertility and having sex, respectively. Anxiety remained stable (20%) over time. Risks of cervical cancer worry and anxiety were both almost double in women without private health insurance (cervical cancer worry: OR = 1.80, 95% CI 1.25–2.61; anxiety: OR = 1.84, 95% CI 1.20–2.84). Younger women (<40 years) had higher risk of fertility worries. Non-Irish women had higher risk of anxiety (OR = 2.13, 95% CI 1.13–4.01). Conclusions Screening-specific worries declined over time but anxiety remained stable. Notable proportions of women still reported adverse outcomes 12 months following colposcopy, with predictors varying between outcomes. Women in socio-demographically vulnerable groups were at greatest risk of adverse psychological outcomes. This information could inform development of interventions to alleviate psychological distress post-colposcopy. Copyright © 2015 John Wiley & Sons, Ltd