An optimized BSCCO/Ag resonator coil for utility use

AC coils made with BSCCO-2223/Ag tapes and operating in liquid nitrogen have a potential for power related applications, e.g., inductors, transformers and current limiters. High-Tc tapes are available from several producers, while access to the coil building know-help is still rather limited, The relevant knowledge and technology suitable for making HTS coils for 50-60 Hz operation is being developed as a part of the current project. To verify the technology, several test solenoids and a first full-scale sub-coil have been manufactured. Electromagnetic, thermal and mechanical analysis of the coils is performed. The electromagnetic analysis focuses on the reduction of the radial magnetic field component in the windings. Voltage-current characteristics and the AC loss data obtained from relevant short sample measurements are applied. A good agreement between calculated and measured V-I curves and losses of the coils is found. A remarkable increase of the critical current and the reduction of the AC loss at the coil edges are predicted and confirmed experimentally. With the losses defined, thermal analysis and optimization of the coil structure are performed numerically followed by measurements for verification. The paper reports on the series of coils developed and explains the features of the projec

Performance test results of a low-loss 1 MVA BSCCO resonator coil system

A high-quality superconducting resonator coil system has been developed in the Netherlands in cooperation with the companies SMIT Transformers and SMIT Draad. The coil system was manufactured in industry, using industrial tooling. It has a reactive power rating of 1 MVA at a frequency of 50 Hz and a temperature of 64 K. The system consists of four concentric solenoidal coils, including 2 km of Bi-2223 conductors from two manufacturers. The coil performance has been optimized by shaping the magnetic field around the coil edges with laminated ferro-magnetic C-cups to reduce the AC loss to about 1 kW at 1 MVA reactive power. The system is operated in a glass-epoxy cryostat at either 64 or 77 K. The resonator coil demonstrates all superconducting elements that are essential for manufacturing superconducting transformers. The construction of the system is finalized and the total system has been tested in various operational configurations. The results of the system test at full power are presented and analyzed.\ud \u

Cognitive functions and quality of life in patients with low‐grade gliomas: The impact of radiotherapy

The role of early radiotherapy in the treatment of low‐grade gliomas is controversial. For this reason the impact of radiotherapy on quality of life was studied in long‐term survivors of biopsy‐proved low‐grade gliomas without signs of tumor recurrence. Twenty patients (age range, 18–66 years) had been treated with early radiotherapy; the other 21 patients (age range, 19–65 years) had undergone surgery or biopsy only. The interval from diagnosis to testing ranged from 1 to 12 years (mean, 3.5 years). Nineteen patients with low‐grade hematological malignancies, surviving 1 to 15 years without central nervous system involvement, served as control subjects. Apart from the neurological and functional status, the patients' cognitive, affective, and psychological status was determined. None of the survivors had significant neurological impairment and the Karnofsky index for them was at least 70. However, more specific examinations of cognitive functions and the affective status (Profile of Mood States) indicated that, compared to the control subjects, the patients with low‐grade gliomas had significantly more cognitive disturbances and suffered more frequently from fatigue and depressed moods. The two groups with low‐grade gliomas, on the other hand, did not differ significantly on any of these measures. It is concluded that radiotherapy did not cause these disturbances and had no negative impact on quality of life in these patients

An optimized BSCCOIAg resonator coil for tility USC

AC coils made with BSCCO-2223/Ag tapes and operating in liquid nitrogen have a potential for power related applications, e.g., inductors, transformers and current limiters. High-T/sub c/ tapes are available from several producers, while access to the coil building know-help is still rather limited, The relevant knowledge and technology suitable for making HTS coils for 50-60 Hz operation is being developed as a part of the current project. To verify the technology, several test solenoids and a first full-scale sub-coil have been manufactured. Electromagnetic, thermal and mechanical analysis of the coils is performed. The electromagnetic analysis focuses on the reduction of the radial magnetic field component in the windings. Voltage-current characteristics and the AC loss data obtained from relevant short sample measurements are applied. A good agreement between calculated and measured V-I curves and losses of the coils is found. A remarkable increase of the critical current and the reduction of the AC loss at the coil edges are predicted and confirmed experimentally. With the losses defined, thermal analysis and optimization of the coil structure are performed numerically followed by measurements for verification. The paper reports on the series of coils developed and explains the features of the project