Comparison of Different Critical Current Density Models for Undoped Monofilamentary Ti-Sheathed MgB2 Tapes

Viljamaa, J.; Rostila, L.; Kòváč, Pavol; Melíšek, T; Hinterberger, A.; Reissner, M.

doi:10.1007/s10948-010-1021-4

Cited by 6 publications

(5 citation statements)

References 41 publications

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“…Undoped samples tend to have their maximum value at lower than the theoretical 0.2 [43], as also seen in Fig. 6.…”

Section: Experimental the Monofilamentarysupporting

confidence: 60%

“…Irreversibility used here is the value of where of 100 is reached. In addition, the theoretical maximum point predicted by grain boundary pinning is indicated by a line at [43], [44]. The curves at 22 K can be seen in Fig.…”

Section: Experimental the Monofilamentarymentioning

confidence: 90%

“…curves are acquired from the magnetic measurements. The method for this is explained in [43]. Irreversibility used here is the value of where of 100 is reached.…”

Section: Experimental the Monofilamentarymentioning

confidence: 99%

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Comparison on Effects of ${\rm B}_{4}{\rm C}$, ${\rm Al}_{2}{\rm O}_{3}$, and SiC Doping on Performance of ${\rm MgB}_{2}$ Conductors

Viljamaa

Kulich

Kòváč

et al. 2011

IEEE Trans. Appl. Supercond.

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Several MgB 2 monofilamentary samples are prepared to evaluate the effects that the doping compounds B 4 C, Al 2 O 3 , and SiC have on critical current density ( c ) and the c dependency of magnetic flux density ( ) of the sample. All of the samples in this study have Nb sheaths and are manufactured using in situ precursor powders and the Powder-in-Tube fabrication method. The amounts of added impurities are 10 wt.% for B 4 C and Al 2 O 3 , and 3, 10, and 20 wt.% for SiC. A reference sample without any doping is also prepared. All of the samples are heat treated between 650 and 800 C for 30 minutes. The transport c ( ) characteristics are measured at 4.2 K and the magnetic c ( ) behavior is obtained in varied temperatures up to 30 K.The changes in connectivity, or effective cross-section, are also evaluated by performing resistivity measurements on the samples after removal of the sheath. Furthermore, the pinning forces of the samples are evaluated from the magnetic measurements.Index Terms-Connectivity, current density, heat treatment, impurity addition, magnetic field effects, MgB 2 .

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“…Undoped samples tend to have their maximum value at lower than the theoretical 0.2 [43], as also seen in Fig. 6.…”

Section: Experimental the Monofilamentarysupporting

confidence: 60%

Section: Experimental the Monofilamentarymentioning

confidence: 90%

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Comparison on Effects of ${\rm B}_{4}{\rm C}$, ${\rm Al}_{2}{\rm O}_{3}$, and SiC Doping on Performance of ${\rm MgB}_{2}$ Conductors

Viljamaa

Kulich

Kòváč

et al. 2011

IEEE Trans. Appl. Supercond.

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“…In non-ideal type 1, as well as in type 2 SC, field trapping may occur. During the process of cooldown in the temperature vicinity of the superconducting phase transition, flux lines can get pinned to normal conducting (NC) impurities [14] or grain boundaries [15]. This process of flux pinning [14] occurs normally only in the Shubnikov phase [16] H c1 < H < H c2 , where the critical current flows within a depth necessary to reduce the field inside the SC to H c1 At field strengths H c1 < H < H p below a penetration field H p , fluxlines will not penetrate through the Bean-Livingston barrier, which is caused by the attraction of the Abrikosov vortices to their 'mirror images' near the surface.…”

Section: Field Trappingmentioning

confidence: 99%

Superconducting shielding with Pb and Nb tubes for momentum sensitive measurements of neutral antimatter

2017

Self Cite

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In this paper we report on measurements and simulations of superconducting tubes in the presence of inhomogeneous externally applied magnetic fields in a cryogenic environment. The shielding effect is studied for two different tube materials, Pb and Nb, employing Hall sensors in a tabletop experiment. The measured internal and external fields of the tubes agree with the theory of the Meissner-Ochsenfeld effect [1], field trapping of type 2 superconductors, phase transitions and tube geometries. The obtained measurements are compared to a finite element simulation. Next, the simulation model is applied to estimate the shielding effect in the vicinity of a cryogenic Penning trap experiment. The controlled suppression of external magnetic fields is important for future precision experiments in atomic and antimatter physics in cryogenic environments.

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“…Including this dependence in the modelling process further complicates the calculation due to the strong coupling introduced between the magnetostatic and the eddy current problems. The most common way to include this dependence in numerical models is through analytical formulas [1][2][3][4][5]. However, analytical approaches rely on fitting parameters to be preliminarily evaluated and consequently suffer from lack of enough accuracy in complicated problems.…”

Section: Introductionmentioning

confidence: 99%

Artificial intelligence-based models for reconstructing the critical current and index-value surfaces of HTS tapes

Russo

Yazdani-Asrami

Scheda

et al. 2022

Supercond. Sci. Technol.

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For modeling superconductors, interpolation and analytical formulas are commonly used to consider the relationship between the critical current density and other electromagnetic and physical quantities. However, look-up tables are not available in all modeling and coding environments, and interpolation methods must be manually implemented. Moreover, analytical formulas only approximate real physics of superconductors and, in many cases, lack a high level of accuracy. In this paper, we propose a new approach for addressing this problem involving artificial intelligence (AI) techniques for reconstructing the critical surface of high temperature superconducting (HTS) tapes and predicting their index value known as n-value. Different AI models were proposed and implemented, relying on a public experimental database for electromagnetic specifications of HTS tapes, including Artificial Neural Networks (ANN), eXtreme Gradient Boosting (XGBoost), and Kernel Ridge Regressor (KRR). The ANN model was the most accurate in predicting the critical current of HTS materials, performing goodness of fit very close to 1 and extremely low RMSE. The XGBoost model proved to be the fastest method, with training computational times under 1 second; whilst KKR could be used as an alternative solution with intermediate performance.

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Comparison of Different Critical Current Density Models for Undoped Monofilamentary Ti-Sheathed MgB2 Tapes

Cited by 6 publications

References 41 publications

Comparison on Effects of ${\rm B}_{4}{\rm C}$, ${\rm Al}_{2}{\rm O}_{3}$, and SiC Doping on Performance of ${\rm MgB}_{2}$ Conductors

Comparison on Effects of ${\rm B}_{4}{\rm C}$, ${\rm Al}_{2}{\rm O}_{3}$, and SiC Doping on Performance of ${\rm MgB}_{2}$ Conductors

Superconducting shielding with Pb and Nb tubes for momentum sensitive measurements of neutral antimatter

Artificial intelligence-based models for reconstructing the critical current and index-value surfaces of HTS tapes

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