Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

The T2K experiment is a long-baseline neutrino oscillation experiment Its main goal is to measure the last unknown lepton sector mixing angle {\theta}_{13} by observing {\nu}_e appearance in a {\nu}_{\mu} beam It also aims to make a precision measurement of the known oscillation parameters, {\Delta}m^{2}_{23} and sin^{2} 2{\theta}_{23}, via {\nu}_{\mu} disappearance studies Other goals of the experiment include various neutrino cross section measurements and sterile neutrino searches The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem

The T2K Experiment

Following updates in the compilation of ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\text{hadrons}$ data, this work presents reevaluations of the hadronic vacuum polarization contributions to the anomalous magnetic moments of the electron (${a}_{e}$), muon (${a}_{\ensuremath{\mu}}$) and tau lepton (${a}_{\ensuremath{\tau}}$), to the ground-state hyperfine splitting of muonium and also updates the hadronic contributions to the running of the QED coupling at the mass scale of the $Z$ boson, $\ensuremath{\alpha}({M}_{Z}^{2})$. Combining the results for the hadronic vacuum polarization contributions with recent updates for the hadronic light-by-light corrections, the electromagnetic and the weak contributions, the deviation between the measured value of ${a}_{\ensuremath{\mu}}$ and its Standard Model prediction amounts to $\mathrm{\ensuremath{\Delta}}{a}_{\ensuremath{\mu}}=(28.02\ifmmode\pm\else\textpm\fi{}7.37)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, corresponding to a muon $g\ensuremath{-}2$ discrepancy of $3.8\ensuremath{\sigma}$.

g − 2 of charged leptons, α ( M Z 2 ) , and the hyperfine splitting of muonium

Now that YBCO-coated conductors have been commercialized, a number of YBCO coils have been developed. However, their basic performances have not been systematically investigated so far. Here, we demonstrate that of a YBCO double pancake coil. The critical current of an epoxy impregnated YBCO double pancake coil was substantially degraded, i.e. the normal voltage appears above 8 A, only 18% of that for the dry coil. It was inferred that degradation occurs if the cumulative radial stress developed during cool down exceeds the critical transverse stress for the YBCO-coated conductor (typically 10 MPa). Under these conditions, the conductor was debonded at the interface between the buffer layer and YBCO layers, or fractured in the YBCO layer itself, causing cracks on the YBCO layer, resulting in a significant decline of the critical current. These negative effects are suppressed if the coils are dry wound or impregnated with paraffin, as the bonding strengths between turns are negligible and therefore turns are separated if the cumulative radial stress tends to be tensile. For non-circular coils in which epoxy impregnation is inevitable, degradation due to cumulative tensile transverse stress is still the major problem.

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Degradation of the performance of a YBCO-coated conductor double pancake coil due to epoxy impregnation

Recent progresses in the second generation REBa2Cu3O7 − x (RE123) coated conductor (CC) have paved a way for the development of superconducting solenoids capable of generating fields well above 23.5 T, i.e. the limit of NbTi−Nb3Sn-based magnets. However, the RE123 magnet still poses several fundamental and engineering challenges. In this work we review the state-of-the-art of conductor and magnet technologies. The goal is to illustrate a close synergetic relationship between evolution of high-field magnets and advancement in superconductor technology. The paper is organized in three parts: (1) the basics of RE123 CC fabrication technique, including latest developments to improve conductor performance and production throughput; (2) critical issues and innovative design concepts for the RE123-based magnet; and (3) an overview of noteworthy ongoing magnet projects.

/pdf/progresses-and-challenges-in-the-development-of-high-field-t8o1mj4zne.pdf

Progresses and challenges in the development of high-field solenoidal magnets based on RE123 coated conductors

The strain dependence of the critical current was studied for YBCO and DyBCO coated conductors with different buffer layers on Hastelloy substrates. A maximum of I/sub c/ was observed for both the YBCO and DyBCO tapes, however the sign of the strain at the I/sub c/ peak was opposite for the two superconductors. A reversible variation of I/sub c/ with applied strain was found and the reversible strain limit was observed to depend on the buffer layer. For the IBAD-CeO/sub 2//YSZ buffered YBCO tapes, I/sub c/ recovers reversibly when the applied strain is reduced starting from 0.30%. For those with an ISD-MgO buffer layer the irreversible degradation starts at a strain less than 0.22%. The reason for this difference is discussed based on microscopic observations. Quenching occurred during V-I measurements after the applied strain exceeded 0.30%, which is close to the yield strain of the composite tape.

Reversible strain dependence of critical current in 100 a class coated conductors

The deformation behavior of the surrounded Cu stabilized YBCO coated conductor based on the Hastelloy substrate and its influence on the critical current were precisely investigated. The mechanical properties were assessed at room temperature and 77 K. The greatest contribution was brought by two metallic components of the Hastelloy substrate and Cu stabilized layers. The internal strain exerted on the superconducting YBCO layer was determined directly by using synchrotron radiation facilities. The thermally induced residual strain with compressive component decreased during the tensile loading and changed to a tensile component at the force free strain (Aff), at which the internal stress becomes zero in the YBCO layer. Beyond Aff, the increasing rate of internal strain slowed down, suggesting brittle behavior, that is, the formation of micro-cracks. The applied strain dependence of the critical current could be divided into two regions. In the reversible region, the strain dependence obeyed the intrinsic strain effect and was well expressed by the Ekin formula. Beyond the reversible limit, the critical current decreased rapidly with strain. The degradation is suggested to be attributed to the formation of cracks in the YBCO layer. The force free strain evaluated from the mechanical properties was 0.26%. On the other hand, the strain at the critical current maximum was observed to be 0.035–0.012%. These facts suggest re-examining the hypothesis supposing that the critical current maximum appears at the force free strain in YBCO coated conductors.

https://iopscience.iop.org/article/10.1088/0953-2048/22/6/065001/pdf

Internal residual strain and critical current maximum of a surrounded Cu stabilized YBCO coated conductor

The strain effect on critical current (Ic(?)) in Y Ba2Cu3O7 ? ? (YBCO) coated conductors was evaluated at temperatures in the range 20?83?K under magnetic fields parallel to the c-axis up to 10?T. The peaked reversible variation of Ic with applied uniaxial strain was confirmed in the self-field at all tested temperatures. The strain sensitivity increases with increasing temperature, resulting in a more pronounced reversible suppression with strain at higher temperature. Interestingly, it was found that the peak strain corresponding to the maximum of Ic shifts to the compressive side with decreasing temperature. Such a peak shift cannot be explained by a change in the thermal residual strain of the YBCO film, suggesting that the peak strain of the Ic(?) in YBCO coated conductors is not determined only by relaxation of the residual strain. The strain sensitivity of Ic(?) at 60?K becomes greater with increasing magnetic field, while the influence of the magnetic field is much less pronounced at 20?K. The in-field Ic(?), including the compressive strain region as well as the tensile region, shows a double peak behavior at low magnetic field at 77 and 83?K. The temperature and magnetic field effect on Ic(?) in YBCO coated conductors is discussed considering flux pinning within the grains and on grain boundaries.

The reversible strain effect on critical current over a wide range of temperatures and magnetic fields for YBCO coated conductors

A new experimental set-up was developed to evaluate the strain dependence of critical current (Ic(ea)) for YBa2Cu3O7−δ (YBCO)-coated conductors under a magnetic field in a variable temperature environment. In this paper, we report the first results on the effect of a magnetic field parallel to the c axis () on Ic(ea) up to 10 T at temperatures of 60–77 K. We found that the magnetic field affects Ic(ea) in a different manner, depending on the field region. When the magnetic field increases from B = 0 T, normalized Ic(ea) is first improved and the optimal situation is realized under the characteristic magnetic field of Bp = 0.2 T at 77 K and Bp = 0.4 T at 70 K, respectively. For higher magnetic field, Ic(ea) degrades further with increasing strain. From the results of a fitting analysis, we confirmed that the strain at the peak of Ic(ea) shifts to higher strain and reaches the maximum value at Bp. The peak shift as a function of magnetic field found in the YBCO-coated conductors is in contrast with the Ic(ea) behavior for conventional low temperature superconducting composites, in which all of the critical parameters are optimized when the intrinsic strain of the superconductor is zero. From the present result, we can conclude that the peak strain of the Ic(ea) curve under a magnetic field is not determined only by the thermal residual strain of the YBCO film in the coated conductor. For the high field region, the curvature of the Ic(ea) curve increases with increasing magnetic field and temperature. It results in a steep decrease in Ic(ea) at high magnetic fields and temperatures.

https://iopscience.iop.org/article/10.1088/0953-2048/21/11/115019/pdf

The intrinsic strain effect on critical current under a magnetic field parallel to the c axis for a MOCVD-YBCO-coated conductor

We investigated the intrinsic strain effect on critical current, Ic, and tensile fracture behaviour in the RE-123 coated conductors (RE =  Y, Dy or Sm) with Hastelloy C-276 substrates. It is found that the SmBCO coated conductors exhibit an intrinsic strain effect on Ic which is similar to that in the DyBCO ones. Ic decreases monotonically with increasing applied tensile strain but it can recover reversibly up to the strain of 0.32% when the strain is relieved. Quenching occurred for the coated conductors with Hastelloy C-276 substrate in the narrow strain region of 0.27–0.35% regardless of the buffer layers and superconducting materials. In order to reveal the reason for such quenching, we measured mechanical properties of the Hastelloy C-276 tapes alone and coated conductors at 77 K. The as-received and as-polished Hastelloy tapes show continuous yielding, which results from homogeneous plastic deformation. On the other hand, the Hastelloy tape annealed at 963 K corresponding to the deposition condition for the superconducting layer exhibits discontinuous yielding. In the annealed Hastelloy tapes, occurrence of Luders bands is observed, indicating that plastic deformation progresses inhomogeneously. Discontinuous yielding is also confirmed in the coated conductor. The yield strains of the coated conductors are almost identical to the strains at quenching. Characteristic fracture behaviour is observed, that transverse crack arrays are initiated from the tape edge and they propagate into the central part. The crack arrays orient to a certain angle to the loading axis, which is similar to that of the Luders bands. The similarities in the initiation site and the angle to the loading axis between the Luders bands and the crack arrays and close values of quenching strains to the yielding one strongly suggest that quenching is attributable to the discontinuous yielding in the Hastelloy substrate.

https://iopscience.iop.org/article/10.1088/0953-2048/18/12/020/pdf

Michinaka Sugano

Papers

Reversible strain dependence of critical current in 100 a class coated conductors

Internal residual strain and critical current maximum of a surrounded Cu stabilized YBCO coated conductor

The reversible strain effect on critical current over a wide range of temperatures and magnetic fields for YBCO coated conductors

The intrinsic strain effect on critical current under a magnetic field parallel to the c axis for a MOCVD-YBCO-coated conductor

Tensile fracture behaviour of RE-123 coated conductors induced by discontinuous yielding in Hastelloy C-276 substrate