In recent years we have successfully designed, built and tested several reluctance motors with YBCO bulk material incorporated into the rotor, working at 77 K. Our last motor type SRE150 was tested up to 200 kW. The aim of our investigations is the construction of motors with extremely high power density and dynamics. In comparison to conventional motor types the advantage of HTS reluctance motors with respect to size and dynamics could be demonstrated. Some fields of possible future applications will be described. These motors show a significant improvement in performance using high quality HTS bulk elements in the rotor. Until now the motor parameters have been limited by the current density which could be obtained in the bulk material at 77 K and by the geometric dimensions of the segments available. Therefore we expect further improvements in the case of these materials. Since the total motor including stator and rotor is working at low temperature we have to optimize the windings and the magnetic circuit to these operation conditions. A new design of a 200 kW motor in order to achieve increased power density and the theoretical results of our calculations will be shown.

Background: Elevated sound levels and low language exposures of preterm infants (< 37 weeks) cared for in the neonatal unit contribute to poorer growth, cognition, language and motor outcomes. These delays can have lasting effects on childhood development and continue throughout adult life. Whilst recommendations have been established for appropriate sound exposure levels in neonatal units, very little is known about the optimal level of language exposure. Objectives: To examine the evidence regarding language exposure, both measured (observational) and prescribed (interventional), in preterm infants (< 37 weeks) cared for in neonatal units and to identify optimal exposure levels to promote neurodevelopment. Search Methods: An electronic search of English-language articles with an open date range was conducted in the PubMed, MEDLINE, Joanna Briggs, CINAHL and Cochrane databases and in Google Scholar. The criteria were limited to original research studies of preterm infants (< 37 weeks) in which language was either measured as it naturally occurred in the neonatal unit environment or through a language intervention. Results: The search produced a total of 2,367 articles, 49 of which were related to language. A full-text review of these articles identified 10 eligible studies and 6 studies from reference searches. Conclusions: Preterm infants experience low levels of language exposure and high sound exposures in neonatal units. There is a lack of conclusive evidence to recommend an optimal level of language exposure to support improved neurodevelopmental outcomes in preterm infants. Further research from large, good-quality clinical trials is required before clear direction can be provided to inform clinical practice.

No abstract

Two new types of HTS electric machine are considered. The first type is hysteresis motors and generators with cylindrical and disc rotors containing bulk HTS elements. The second type is reluctance motors with compound HTS-ferromagnetic rotors. The compound HTS-ferromagnetic rotors, consisting of joined alternating bulk HTS (YBCO) and ferromagnetic (iron) plates, provide a new active material for electromechanical purposes. Such rotors have anisotropic properties (ferromagnetic in one direction and diamagnetic in the perpendicular one). Theoretical and experimental results for HTS hysteresis and reluctance motors are presented. A series of hysteresis HTS motors with output power rating from 1 kW (at 50 Hz) up to 4 kW (at 400 Hz) and a series of reluctance HTS motors with output power 2-18.5 kW (at 50 Hz) were constructed and successfully tested. It was shown that HTS reluctance motors could reach two to five times better overall dimensions and specific power than conventional asynchronous motors of the same size and will have higher values of power factor (cos φ⩾0.7 to 0.8).

OSWALD Elektromotoren GmbH, Miltenberg, Germany, is experienced in direct linear motors with high power density. For some special applications the requirements are extremely demanding and almost beyond reach, even for state-of-the-art linear motors operated at room temperature. In order to obtain even higher power density, and hence also increased acceleration, we have to develop a new technology for linear motors. In this paper we propose a round superconducting linear motor. The stator windings will be made of YBCO coated conductors in the shape of double pancake coils. The frequency will be limited to approximately 10 Hz for this application. The actuator will be provided with NdFeB permanent magnets. The special cryogenic design will be discussed. The cooling of the stator will be provided by lN2 at 77 K or lower. The calculated force of this SC linear motor is 10 000 N. The force density will be 2–3 times more than the normal conducting counterpart of the same dimensions.