Use of thermal gradients for control of vortex matter in mesoscopic superconductors

This article examines the vortex matter of mesoscopic superconductors with numerous vortex states that do not exist in bulk superconductors. Using scanning tunneling microscopy/spectroscopy, it investigates the organization of vortex cores at different levels of confinement. The article begins with a discussion of the basic properties of quantum vortices in superconductors and experimental requirements for studying vortex confinement phenomena. It then considers the effect of sample size and shape on vortex distribution and pinning, along with the resulting ultra-dense configurations that cannot be achieved in bulk superconductors. It also describes the peculiar features of vortices in atomically thin superconductors having mixed Abrikosov–Josephson vortices.

Download Full-text

Vortex matter in mesoscopic superconductors

Physica B Condensed Matter ◽

10.1016/s0921-4526(98)00570-5 ◽

1998 ◽

Vol 256-258 ◽

pp. 610-617 ◽

Cited By ~ 21

Author(s):

J.J. Palacios

Keyword(s):

Vortex Matter ◽

Mesoscopic Superconductors

Download Full-text

Fission Gas Bubbles in Fractured UO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101177 ◽

1968 ◽

Vol 26 ◽

pp. 286-287

Author(s):

O. M. Katz

Keyword(s):

Electron Microscopy ◽

Thermal Gradient ◽

Gas Bubbles ◽

Inert Gas ◽

Thermal Gradients ◽

Fission Gas ◽

Beam Heating ◽

Limited Application ◽

Bubble Characteristics ◽

Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

Download Full-text

BOILING HEAT TRANSFER ENHANCEMENT ON STRUCTURED SURFACES WITH ENGINEERED THERMAL GRADIENTS AND NUCLEATION SITES

Proceeding of First Thermal and Fluids Engineering Summer Conference ◽

10.1615/tfesc1.mph.012980 ◽

2016 ◽

Author(s):

Md Mahamudur Rahman ◽

Emre Olceroglu ◽

Matthew McCarthy

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Boiling Heat Transfer ◽

Thermal Gradients ◽

Transfer Enhancement ◽

Structured Surfaces ◽

Nucleation Sites

Download Full-text

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

Revista Liberato ◽

10.31514/rliberato.2020v21n35.p75 ◽

2020 ◽

pp. 75-86

Author(s):

Sergio Antonio Camargo ◽

Lauro Correa Romeiro ◽

Carlos Alberto Mendes Moraes

Keyword(s):

Thermal Fatigue ◽

Cooling System ◽

Fatigue Cracks ◽

Cooling Water ◽

Thermal Conditions ◽

Thermal Gradients ◽

Ansys Software ◽

Cooling Systems ◽

Thermal Fatigue Cracks ◽

Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

Download Full-text

Toward living nanomachines

10.1093/oso/9780199674923.003.0039 ◽

2018 ◽

Author(s):

Christof Mast ◽

Friederike Möller ◽

Moritz Kreysing ◽

Severin Schink ◽

Benedikt Obermayer ◽

...

Keyword(s):

Molecular Evolution ◽

Thermal Gradient ◽

Molecular Level ◽

Minimal System ◽

Thermal Gradients ◽

Temperature Oscillations ◽

Fluid Convection ◽

Inanimate Matter ◽

High Concentrations ◽

Periodic Temperature

How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

Download Full-text