Search

Your search keyword '"Coombs, Tim A."' showing total 44 results
Start Over Author "Coombs, Tim A." Publication Year Range Last 3 years
44 results on '"Coombs, Tim A."'

10. Progress in the Design and Production of Transverse Gradient Coils for 1 T HTS Portable MRI Instrument

Author

Shah, Adil, Ozturk, Yavuz, Patel, Ismail, Hu, Jintao, Wei, Haigening, Wang, Qi, Hao, Luning, Shen, Boyang, and Coombs, Tim

Abstract

Magnetic resonance imaging (MRI) scanner consists of five major components: The main magnet, a gradient system, an RF coil system, a receiver, and a computer system for data acquisition. Gradient coils are an integral part of an MRI system, used for spatially encoding the MRI signal via modulations on the main magnetic field. In this article, we discuss the in-house design and production method of a particular gradient coil aimed as a part of a portable MRI instrument with a 1 T high-temperature superconducting (HTS) main magnet. We aim to reveal a clear path for those who want to follow.

Published
2024
Full Text
View/download PDF

14. Roadmap on artificial intelligence and big data techniques for superconductivity

Author

Yazdani-Asrami, Mohammad, primary, Song, Wenjuan, additional, Morandi, Antonio, additional, De Carne, Giovanni, additional, Murta-Pina, Joao, additional, Pronto, Anabela, additional, Oliveira, Roberto, additional, Grilli, Francesco, additional, Pardo, Enric, additional, Parizh, Michael, additional, Shen, Boyang, additional, Coombs, Tim, additional, Salmi, Tiina, additional, Wu, Di, additional, Coatanea, Eric, additional, Moseley, Dominic A, additional, Badcock, Rodney A, additional, Zhang, Mengjie, additional, Marinozzi, Vittorio, additional, Tran, Nhan, additional, Wielgosz, Maciej, additional, Skoczeń, Andrzej, additional, Tzelepis, Dimitrios, additional, Meliopoulos, Sakis, additional, Vilhena, Nuno, additional, Sotelo, Guilherme, additional, Jiang, Zhenan, additional, Große, Veit, additional, Bagni, Tommaso, additional, Mauro, Diego, additional, Senatore, Carmine, additional, Mankevich, Alexey, additional, Amelichev, Vadim, additional, Samoilenkov, Sergey, additional, Yoon, Tiem Leong, additional, Wang, Yao, additional, Camata, Renato P, additional, Chen, Cheng-Chien, additional, Madureira, Ana Maria, additional, and Abraham, Ajith, additional

Published
2023
Full Text
View/download PDF

15. Pulse Field Magnetization (PFM) With Different HTS Stacked Tape Architecture for Electrical Machine

Author

Wei, Haigeing, Wang, Qi, Hao, Luning, Hu, Jintao, Patel, Ismail, Shah, Adil, Wu, Yuyang, Huang, Zhipeng, and Coombs, Tim

Abstract

High temperature superconducting (HTS) stacks of superconducting tapes provide a solution for all-superconducting electrical machines since they could work as trapped-field magnets. Most experiments with these stacks use pieces of tapes with relatively small areas as wider tapes are more difficult to acquire, therefore in this paper we investigate substitutions for these wider tapes to be implemented in superconducting electrical machines. With different stack architectures and substrate materials made by different manufacturers with different widths, the magnetizing effect using pulse field magnetization (PFM) would be different. To explore the differences of this effect, different stacks are tested in a modified synchronous machine designed by ASuMED under liquid nitrogen conditions. By changing the stacks of the tape and testing them under the same condition, the characteristics of the trapped flux, magnetization and demagnetization are affected, the difference is then compared to a COMSOL finite element model using an electromagnetic-thermal coupled model to investigate this effect. This paper shows the experimental setup for a PFM for HTS stacked coated conductor (CC) within an electrical machine, different stack architectures are tested and simulated, and the magnetic characteristics are compared and discussed, where the simulation and experiment agree in a certain degree, and the sectioned HTS CC stacks can proven to be useful in an electrical machine.

Published
2024
Full Text
View/download PDF

16. Assessing the content validity of the revised Health of the Nation Outcome Scales 65+: the HoNOS Older Adults.

Author

Harris, Meredith G., Tapp, Caley, Arnautovska, Urska, Coombs, Tim, Dickson, Rosemary, Smith, Mark, Jury, Angela, Lai, Jennifer, James, Mick, Painter, Jon, and Burgess, Philip M.

Subjects
MENTAL health services, OLDER people, TEST validity
Abstract

Aims and method Recently, the Health of the Nation Outcome Scales 65+ (HoNOS65+) were revised. Twenty-five experts from Australia and New Zealand completed an anonymous web-based survey about the content validity of the revised measure, the HoNOS Older Adults (HoNOS OA). Results All 12 HoNOS OA scales were rated by most (=75%) experts as 'important' or 'very important' for determining overall clinical severity among older adults. Ratings of sensitivity to change, comprehensibility and comprehensiveness were more variable, but mostly positive. Experts' comments provided possible explanations. For example, some experts suggested modifying or expanding the glossary examples for some scales (e.g. those measuring problems with relationships and problems with activities of daily living) to be more older adult-specific. Clinical implications Experts agreed that the HoNOS OA measures important constructs. Training may need to orient experienced raters to the rationale for some revisions. Further psychometric testing of the HoNOS OA is recommended. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

22. Developing an International Standard Set of Patient-Reported Outcome Measures for Psychotic Disorders

Author

McKenzie, Emily, Matkin, Lucy, Sousa Fialho, Luz, Emelurumonye, Ifeoma Nneka, Gintner, Timea, Ilesanmi, Christiana, Jagger, Beth, Quinney, Shannon, Anderson, Elizabeth, Baandrup, Lone, Bakhshy, Amrit Kumar, Brabban, Alison, Coombs, Tim, Correll, Christoph U., Cupitt, Caroline, Keetharuth, Anju Devianee, Lima, Dania Nimbe, McCrone, Paul, Moller, Mary, Mulder, Cornelis L., Roe, David, Sara, Grant, Shokraneh, Farhad, Sin, Jacqueline, Woodberry, Kristen A., Addington, Donald, McKenzie, Emily, Matkin, Lucy, Sousa Fialho, Luz, Emelurumonye, Ifeoma Nneka, Gintner, Timea, Ilesanmi, Christiana, Jagger, Beth, Quinney, Shannon, Anderson, Elizabeth, Baandrup, Lone, Bakhshy, Amrit Kumar, Brabban, Alison, Coombs, Tim, Correll, Christoph U., Cupitt, Caroline, Keetharuth, Anju Devianee, Lima, Dania Nimbe, McCrone, Paul, Moller, Mary, Mulder, Cornelis L., Roe, David, Sara, Grant, Shokraneh, Farhad, Sin, Jacqueline, Woodberry, Kristen A., and Addington, Donald

Abstract

OBJECTIVE: The objective of this project was to develop a set of patient-reported outcome measures for adolescents and adults who meet criteria for a psychotic disorder. METHODS: A research team and an international consensus working group, including service users, clinicians, and researchers, worked together in an iterative process by using a modified Delphi consensus technique that included videoconferencing calls, online surveys, and focus groups. The research team conducted systematic literature searches to identify outcomes, outcome measures, and risk adjustment factors. After identifying outcomes important to service users, the consensus working group selected outcome measures, risk adjustment factors, and the final set of outcome measures. International stakeholder groups consisting of >100 professionals and service users reviewed and commented on the final set. RESULTS: The consensus working group identified four outcome domains: symptoms, recovery, functioning, and treatment. The domains encompassed 14 outcomes of importance to service users. The research team identified 131 measures from the literature. The consensus working group selected nine measures in an outcome set that takes approximately 35 minutes to complete. CONCLUSIONS: A set of patient-reported outcome measures for use in routine clinical practice was identified. The set is free to service users, is available in at least two languages, and reflects outcomes important to users. Clinicians can use the set to improve clinical decision making, and administrators and researchers can use it to learn from comparing program outcomes.

Published
2022

25. Field Cancelling Effect in Double-layer Roebel Tapes

Author

Hao, Luning, primary, Patel, Ismail, additional, Yang, Jiabin, additional, Hu, Jintao, additional, Shah, Adil, additional, Wei, Haigening, additional, Tian, Mengyuan, additional, Wang, Qi, additional, Shen, Boyang, additional, and Coombs, Tim A, additional

Published
2022
Full Text
View/download PDF

28. Numerical Study on AC Loss Characteristics of Conductor on Round Core Cables Under Transport Current and Magnetic Field

Author

Yang, Jiabin, primary, Tian, Mengyuan, additional, Ma, Jun, additional, Ozturk, Yavuz, additional, Li, Chao, additional, Hu, Jintao, additional, Gawith, James, additional, Shah, Adil, additional, Patel, Ismail, additional, Wei, Haigening, additional, Hao, Luning, additional, Shen, Boyang, additional, and Coombs, Tim, additional

Published
2021
Full Text
View/download PDF

31. Quench Protection Modeling of an HTS Magnet for MRI System

Author

Shen, Boyang, primary, Chen, Xiao yuan, additional, Liu, Huajun, additional, Ni, Zhipeng, additional, Shi, Yi, additional, Guo, Liang, additional, Zhang, Xintao, additional, Sheng, Jie, additional, Xie, Qi, additional, Zeng, Lei, additional, Chen, Wei, additional, Yang, Xinsheng, additional, Ozturk, Yavuz, additional, Fu, Lin, additional, Tian, Mengyuan, additional, Yang, Jiabin, additional, and Coombs, Tim, additional

Published
2021
Full Text
View/download PDF

35. Losses in the Saturated Iron-Core Superconducting Fault Current Limiter For VSC-HVDC System

Author

Shen, Boyang, primary, Chen, Xiaoyuan, additional, Fu, Lin, additional, Zhang, Mingshun, additional, Jiang, Shan, additional, Sheng, Jie, additional, Wang, Wei, additional, Zhai, Yujia, additional, Yuan, Yupeng, additional, Gao, Shuo, additional, Soomro, Wafa Ali, additional, Guo, Youguang, additional, Wang, Sheng, additional, Li, Chuanyue, additional, Bian, Xingming, additional, Liu, Hongwei, additional, Zheng, Zhongting, additional, Li, Chao, additional, Zhang, Runtao, additional, Ozturk, Yavuz, additional, Liu, Yi, additional, Yang, Jiabin, additional, and Coombs, Tim, additional

Published
2021
Full Text
View/download PDF

37. Superconducting Conductor on Round Core (CORC) Cables: 2D or 3D Modeling?

Author

Shen, Boyang, primary, Chen, Xiaoyuan, additional, Fu, Lin, additional, Jiang, Shan, additional, Gou, Huayu, additional, Sheng, Jie, additional, Huang, Zhen, additional, Wang, Wei, additional, Zhai, Yujia, additional, Yuan, Yupeng, additional, Gao, Shuo, additional, Wang, Sheng, additional, Li, Chuanyue, additional, Chen, Wei, additional, Mu, Shuai, additional, Zhou, Qian, additional, Song, Wenjuan, additional, Pei, Xiaoze, additional, Ozturk, Yavuz, additional, Gawith, James, additional, Liu, Yi, additional, Patel, Ismail, additional, Tian, Mengyuan, additional, Yang, Jiabin, additional, and Coombs, Tim, additional

Published
2021
Full Text
View/download PDF

39. A Simplified Model of the Field Dependence for HTS Conductor on Round Core (CORC) Cables

Author

Shen, Boyang, primary, Chen, Xiaoyuan, additional, Fu, Lin, additional, Zhang, Mingshun, additional, Chen, Yu, additional, Sheng, Jie, additional, Huang, Zhen, additional, Wang, Wei, additional, Zhai, Yujia, additional, Yuan, Yupeng, additional, Soomro, Wafa Ali, additional, Guo, Youguang, additional, Bian, Xingming, additional, Liu, Hongwei, additional, Ozturk, Yavuz, additional, Tian, Mengyuan, additional, Hao, Luning, additional, Hu, Jintao, additional, Wei, Haigening, additional, Shah, Adil, additional, Patel, Ismail, additional, Yang, Jiabin, additional, and Coombs, Tim, additional

Published
2021
Full Text
View/download PDF

43. Applied Superconductivity and Electromagnetic Devices - Principles and Current Exploration Highlights.

Author

Jin, Jianxun, Sheng, Guang, Bi, Yanfang, Song, Yuntao, Liu, Xiaolong, Chen, Xin, Li, Qiang, Deng, Zigang, Zhang, Weihua, Zheng, Jun, Coombs, Tim, Shen, Boyang, Zhu, Jiamin, Zhao, Yong, Wang, Jianhua, Xiang, Bin, Tang, Yuejin, Ren, Li, Xu, Ying, and Shi, Jing

Subjects
ELECTROMAGNETIC devices, SUPERCONDUCTIVITY, SUPERCONDUCTORS, MAGNETIC suspension, HIGH temperature superconductors, MAGNETS, SUPERCONDUCTING magnets
Abstract

With regard to the state-of-the-art technologies in the fields of applied superconductivity and electromagnetic devices, research and development highlights are presented. The recent progress and achievement described with principle and technical details include mainly i) applied superconducting materials; ii) superconducting magnets and their applications such as in ITER and Tokamaks; iii) high Tc superconducting (HTS) magnetic levitation and applications; iv) HTS smart grids; v) superconducting and electromagnetic material modelling and characterization; and vi) advanced electromagnetic devices. The applied superconductivity technology and availability are especially focused and verified with the trend of development prospection. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

44. Electromagnetic-thermal characteristics of Conductor on Round Core (CORC) cables

Author

Yang, Jiabin and Coombs, Tim

Subjects
HTS-CC, CORC cable, Terminal resistance, Quench, AC loss, CORC magnet, Persistent current switch, Magnet charging
Abstract

Second-generation high-temperature superconducting (2G HTS) tapes, known as coated conductors (HTS-CCs), showing high current density in a high magnetic field, are already commercially available. As a cabling concept, Conductor on Round Core (CORC) cables consisting of a cylindrical former and multiple helically bent HTS-CCs, exhibit more significant current-carrying capacity while reducing alternating current (AC) losses. They are promising candidates for low-loss power transmission and low-inductance high-field magnets. This thesis carries out exhaustive research on the electromagnetic-thermal characteristics of CORC cables, and a charging method for a CORC magnet is proposed. After a brief description of superconductivity fundamentals, the thesis starts with introducing HTS-CCs, the components of CORC cables. The thermal quench performance of a single HTS-CC is studied first, indicating its low normal zone propagation velocity (NZPV, a few cm/s) and minimum quench energy (MQE, less than 0.1 Joule) in the liquid nitrogen bath (under adiabatic conditions). Then, the study of its AC transport loss is conducted, revealing that the hysteresis loss and eddy current loss coexist. The eddy current loss is dependent on the current frequency when the unit of the transport loss is J/cyclem/m. Next, the thesis goes to the CORC cable. The direct current (DC) characteristics are investigated, explaining the tape arrangement on the helical structure. Also, the critical current of a single-layer CORC cable is measured, quantifying the inhomogeneous terminal resistance among individual HTS-CCs (0.5−3.4 μΩ). Following the DC characteristics, the thesis analysed the thermal quench behaviour of the CORC cable under DC transport currents. Experiments are performed to observe the thermally propagating normal zones, especially when a heating disturbance occurs in the assembled HTS-CCs with different terminal resistance. A 3D multi-physics simulation using electrostatic and heat transfer modules is developed to assess the influence of transport current and terminal resistance on quench propagation. In particular, the integration of the coper former increases the MQE to the order of a few Joules but makes it possible for all HTS-CCs to quench at a low current level. Then, research shifts from DC to AC, the AC transport loss analysis. Measurements are implemented first to validate the subsequent simulation models developed by a 3D electromagnetic module. Current density and magnetic field distribution are simulated both in a double-layer and a single-layer CORC cable; the loss level between those two structures is benchmarked against a single HTS-CC. Besides, while the helical structure of CORC cables reduces the transport loss, an additional in-phase background magnetic field can magnify the losses several times to dozens of times. Finally, a CORC magnet is explored, meaning bending the CORC cable into a solenoid. This magnet is low-inductive due to the parallel-connected currents. It is charged with a superconducting Persistent Current Switch (PCS), forming a closed-loop magnet to maintain the superconducting current. An overcurrent is used to trigger the PCS because a simple structure is preferred by this complex magnet, and the gradual rising overcurrent will not cause too much heat burden for the cryogenic system. In addition, the low closed-loop inductance of this magnet (a few μH) is experimentally measured using the circuit resistance and discharging curve. Overall, this thesis concluded the electromagnetic-thermal qualities of CORC cables involving the current capacity, thermal stability, and AC transport loss level, promoting the application from superconducting tapes to superconducting cables. Also, the first study of the charging characteristics of a CORC magnet provides an essential reference for its utilisation in high-field superconducting magnets. More broadly, those developed 3D simulation techniques and experimental platforms in the LabView can benefit all the superconductivity research.

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results