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The conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables. [ABSTRACT FROM AUTHOR]

This paper presents an approach for deriving the continuum sensitivity of superconducting systems operating at critical current densities and an optimization method based on the continuum sensitivity. In the sensitivity problem, the superconducting systems is represented by a variational state equation, wherein the magnetic permeability depends on the magnetic field, which is transformed from a state equation with a field-dependent source. The design sensitivity is derived using the material derivative concept of continuum mechanics and the adjoint variable method. The adjoint system has a material property represented as a symmetric tensor that contains the sensitivity of the current density with respect to the magnetic field. The design sensitivity is represented in the analytical form of a surface integral on the interface between the superconducting material and its surroundings, which depends on the sensitivity of the current density. The optimization scheme is constructed based on the continuum design sensitivity. In the design optimization, the level set method is used to express the shape variation of the superconducting materials. The numerical example of infinite solenoids demonstrates that the design sensitivity provides an accurate design solution considering the critical current condition. In addition, the design example of a magnetic resonance imaging solenoid shows that the derived design sensitivity has the inherent ability for attaining the compact design by treating the input current of a superconducting system as a critical condition. [ABSTRACT FROM AUTHOR]

This paper presents an investigation on ac losses of superconducting bulk with the help of finite element software of Comsol Multiphysics. The calculation ac loss result was compared with that from analytical formulas for type-II superconducting slab and cylinder. Three different geometries of the columnar bulk are analyzed, which are bulk with no core, bulk with a central columnar air core, and bulk with a central columnar iron core. The core is parallel to the c-axis of bulk. The temperature dependence of the ac loss is presented, and the thermal behavior of the bulk is analyzed by associating ac loss with heat transfer characteristic through the external surface of the bulk sample. [ABSTRACT FROM AUTHOR]

Based on conventional approaches for the integration of resistive-type superconducting fault current limiters (SFCLs) on electric distribution networks, SFCL models largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of an SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density, characteristic of high temperature superconductors. Our results are compared to the step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, to study the impact of these protection strategies on the performance of the overall electricity network. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions were simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies. Consequently, we have shown that the incorporation of the E- J characteristics and thermal properties of the superconductor at the simulation level of electric power systems, is crucial for estimations of reliability and determining the optimal locations of resistive type SFCLs in distributed power networks. Our results may help decision making by distribution network operators regarding investment and promotion of SFCL technologies, as it is possible to determine the maximum number of SFCLs necessary to protect against different fault conditions at multiple locations. [ABSTRACT FROM AUTHOR]

Purpose: Inpatient psychiatric units are dynamic in nature, potentially creating a different treatment experience for each person, which may be difficult to quantify. Among the goals of this multi-centre service evaluation project was an assessment of shift-to-shift changes in unit-level events and their impact on the social-emotional environment. Methods: Over 1 year, various nurse-completed logs were used within the 11 participating Australian psychiatric units ( n = 5,546 admissions) to record patient- and unit-level events per shift, including ratings of the overall social-emotional climate using a novel shift climate ratings (SCR) scale ( n = 8,176 shifts). These were combined with admission-level patient characteristics to investigate shift climate profiles and correlates. Results: Occupancy rates averaged 88% and two-thirds of admissions were involuntary. The psychometric performance of the SCR scale was considered to be satisfactory (e.g., high internal consistency, unidimensional factor structure, and evidence of discriminant and predictive validity). A series of hierarchical regressions revealed considerable variation in SCR total scores, with poorer climates being significantly associated with: day/afternoon shifts; higher occupancy levels; higher proportions of experienced staff, and male, older, or involuntary patients; higher rates of less serious aggressive incidents; reporting of additional staffing demands; and unit location in a stand-alone psychiatric hospital. Conclusions: The day-to-day social-emotional climate can have important consequences for patient engagement and recovery. Improved understanding of the role played by unit, staff and patient characteristics, together with routine monitoring, should facilitate the development and evaluation of targeted interventions to reduce adverse incidents and improve the overall social-emotional climate. [ABSTRACT FROM AUTHOR]

Relationships within acute psychiatric units between patient-level experiences and events and fluctuations in mental state have rarely been examined. Data from a multi-centre service evaluation (11 units, 5,546 admissions) were used to examine mental state patterns and associations with clinical characteristics, events and adverse incidents. During the 12-month evaluation period, nursing staff completed shift-level ratings using a new rating scale, the observed mental state (OMS) scale, which assessed active psychopathology (emotional distress, disinhibition, psychosis, cognitive impairment) and withdrawal (45,885 sets of day/afternoon shift ratings). The OMS scale performed satisfactorily and is worth considering elsewhere (e.g., active psychopathology: internal consistency, α = 0.72; short-term stability, r = 0.72; sensitivity to change, adjusted standardised difference, ASD = 0.71). Levels of active psychopathology were much higher on shifts in which reportable (ASD = 1.47) and less serious aggression occurred (ASD = 1.44), compared with other shifts in which pro re nata medications were also administered (ASD = 0.76), suggesting that medication usage often followed these events, and possibly that agitation and distress levels either rose rapidly or went initially unnoticed on these shifts. Although mental state improved steadily across the admission, one-fifth of the patients with schizophrenia received OMS psychosis ratings in the moderate to severe range during the days prior to discharge. Observed mental state ratings were strongly linked with diagnosis and reflected key events and incidents. Routine recording using the OMS scale may assist clinical decision-making and evaluation in acute psychiatric units. [ABSTRACT FROM AUTHOR]