51,060 research outputs found
Magnetocaloric effect and magnetic cooling near a field-induced quantum-critical point
The presence of a quantum critical point (QCP) can significantly affect the
thermodynamic properties of a material at finite temperatures T. This is
reflected, e.g., in the entropy landscape S(T, r) in the vicinity of a QCP,
yielding particularly strong variations for varying the tuning parameter r such
as pressure or magnetic field B. Here we report on the determination of the
critical enhancement of near a B-induced QCP via
absolute measurements of the magnetocaloric effect (MCE), , and demonstrate that the accumulation of entropy around the QCP can be
used for efficient low-temperature magnetic cooling. Our proof of principle is
based on measurements and theoretical calculations of the MCE and the cooling
performance for a Cu-containing coordination polymer, which is a very
good realization of a spin-1/2 antiferromagnetic Heisenberg chain - one of the
simplest quantum-critical systems.Comment: 21 pages, 4 figure
Physics at a 100 TeV pp collider: Higgs and EW symmetry breaking studies
This report summarises the physics opportunities for the study of Higgs
bosons and the dynamics of electroweak symmetry breaking at the 100 TeV pp
collider.Comment: 187 pages, 94 figures. Chapter 2 of the "Physics at the FCC-hh"
Repor
The bias-extension test for the analysis of in-plane shear properties of textile composite reinforcements and prepregs: a review
The bias-extension test is a rather simple experiment aiming to determine in-plane shear properties of textile composite reinforcements. However the mechanics during the test involves fibrous material at large shear strains and large rotations of the fibres. Several aspects are still being studied and are not yet modeled in a consensual manner. The standard analysis of the test is based on two assumptions: inextensibility of the fibers and rotations at the yarn crossovers without slippage. They lead to the development of zones with constant fibre orientations proper to the bias-extension test. Beyond the analysis of the test within these basic assumptions, the paper presents studies that have been carried out on the lack of verification of these hypothesis (slippage, tension in the yarns, effects of fibre bending). The effects of temperature, mesoscopic modeling and tension locking are also considered in the case of the bias-extension test
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