Reversible magnetization, critical fields, and vortex structure in grain-alignedYBa2Cu4O8

Background: WSN is a network of smart tiny electromechanical devices named as sensors. Sensors perform various tasks like sensing the environment as per its range, transmit the data using transmission units, store the data in the storage unit and perform an action based on captured data. As they are installed in an unfriendly environment, to recharge the sensors are not possible every time which leads to a limited lifetime of a network. To enhance the life of a sensor network, the network required energy-efficient protocols. Various energy-efficient MAC protocols are developed by Research community, but very few of them are integrated with the priority-based environment which performs the priority-based data transmission. Another challenge of WSN is, most of the WSN areas are delay-sensitive because it is implemented in critical fields like military, disaster management, and health monitoring. Energy, Delay, and throughput are major quality factors that affect the sensor network. Objective: In this paper, the aim is to design and develop a MAC Protocol for a field like the military where the system requires energy efficiency and priority-based data transmission. Method: In the proposed model, the cluster-based network with priority queues are formed that can achieve higher power efficiency and less delay for sensitive data. Results: In this research simulation of Proposed MAC, TMAC and SMAC are done with different numbers of nodes, same inter-packet intervals, and variant inter-packet intervals. Based on the script simulation, result graphs are generated. Conclusion: The proposed work achieves greater lifetime compared to TMAC and SMAC using priority-based data transmission.

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Changes in the upper critical fields and critical currents of Nb3Sn and V3Ga owing to neutron radiation damage

Applied Physics Letters ◽

10.1063/1.89277 ◽

1977 ◽

Vol 30 (12) ◽

pp. 662-664 ◽

Cited By ~ 12

Author(s):

C. L. Snead

Keyword(s):

Radiation Damage ◽

Neutron Radiation ◽

Critical Currents ◽

Critical Fields ◽

Upper Critical Fields ◽

Neutron Radiation Damage

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Experimental signatures of nodeless multiband superconductivity in a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ single crystal

Scientific Reports ◽

10.1038/s41598-021-92709-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chanhee Kim ◽

Dilip Bhoi ◽

Yeahan Sur ◽

Byung-Gu Jeon ◽

Dirk Wulferding ◽

...

Keyword(s):

Magnetic Field ◽

Single Crystal ◽

Zero Magnetic Field ◽

Anisotropy Ratio ◽

Strong Temperature Dependence ◽

Critical Fields ◽

Band Theory ◽

Plane Field ◽

Low Field ◽

Out Of Plane

AbstractIn order to understand the superconducting gap nature of a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 single crystal with $$T_{c} = 3.13 \text { K}$$ T c = 3.13 K , in-plane thermal conductivity $$\kappa $$ κ , in-plane London penetration depth $$\lambda _{\text {L}}$$ λ L , and the upper critical fields $$H_{c2}$$ H c 2 have been investigated. At zero magnetic field, it is found that no residual linear term $$\kappa _{0}/T$$ κ 0 / T exists and $$\lambda _{\text {L}}$$ λ L follows a power-law $$T^n$$ T n (T: temperature) with n = 2.66 at $$T \le \frac{1}{3}T_c$$ T ≤ 1 3 T c , supporting nodeless superconductivity. Moreover, the magnetic-field dependence of $$\kappa _{0}$$ κ 0 /T clearly shows a shoulder-like feature at a low field region. The temperature dependent $$H_{c2}$$ H c 2 curves for both in-plane and out-of-plane field directions exhibit clear upward curvatures near $$T_c$$ T c , consistent with the shape predicted by the two-band theory and the anisotropy ratio between the $$H_{c2}$$ H c 2 (T) curves exhibits strong temperature-dependence. All these results coherently suggest that $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 is a nodeless, multiband superconductor.

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Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators

Scientific Reports ◽

10.1038/s41598-021-87119-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chris Sundahl ◽

Junki Makita ◽

Paul B. Welander ◽

Yi-Feng Su ◽

Fumitake Kametani ◽

...

Keyword(s):

High Performance ◽

High Energy ◽

Particle Accelerators ◽

Quality Factors ◽

Critical Fields ◽

Linear Accelerators ◽

Cross Sectional ◽

Low Field ◽

Superconducting Radio Frequency

AbstractSuperconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 1010 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200–240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb3Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb3Sn, it has been proposed to coat Nb cavities with thin film Nb3Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb3Sn/Al2O3 multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al2O3 and Nb3Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

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The Stationary Concentrated Vortex Model

Climate ◽

10.3390/cli9030039 ◽

2021 ◽

Vol 9 (3) ◽

pp. 39

Author(s):

Oleg Onishchenko ◽

Viktor Fedun ◽

Wendell Horton ◽

Oleg Pokhotelov ◽

Natalia Astafieva ◽

...

Keyword(s):

Vortex Structure ◽

Radial Direction ◽

Symmetry Axis ◽

Outer Part ◽

Vertical Direction ◽

Axially Symmetric ◽

New Model ◽

Vortex Model ◽

Axis Of Symmetry ◽

Good Agreement

A new model of an axially-symmetric stationary concentrated vortex for an inviscid incompressible flow is presented as an exact solution of the Euler equations. In this new model, the vortex is exponentially localised, not only in the radial direction, but also in height. This new model of stationary concentrated vortex arises when the radial flow, which concentrates vorticity in a narrow column around the axis of symmetry, is balanced by vortex advection along the symmetry axis. Unlike previous models, vortex velocity, vorticity and pressure are characterised not only by a characteristic vortex radius, but also by a characteristic vortex height. The vortex structure in the radial direction has two distinct regions defined by the internal and external parts: in the inner part the vortex flow is directed upward, and in the outer part it is downward. The vortex structure in the vertical direction can be divided into the bottom and top regions. At the bottom of the vortex the flow is centripetal and at the top it is centrifugal. Furthermore, at the top of the vortex the previously ascending fluid starts to descend. It is shown that this new model of a vortex is in good agreement with the results of field observations of dust vortices in the Earth’s atmosphere.

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