Thermal conductivity of a gas of rotating diamagnetic molecules in an applied magnetic field

Vacuum ◽  
1967 ◽  
Vol 17 (7) ◽  
pp. 426
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Applied Magnetic Field

Experimental Investigation of Magnetically-Induced Thermal Conductance Variations in a Ferromagnetic Nanofluid

2011 ◽  
Author(s):  
Alexander M. Gardner ◽  
Indira Seshadri ◽  
Ganpati Ramanath ◽  
Theodorian Borca-Tasciuc
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Magnetic Fields ◽  
Thermal Resistance ◽  
Applied Magnetic Field ◽  
Thermal Conductance ◽  
Flow Characteristics ◽  
Test Apparatus ◽  
The Subject

Ferrofluids have been the subject of great interest in engineering because of their unique flow characteristics under magnetic fields (Rosensweig, 1987). However, there are limited experiments which show the potential of ferrofluids to undergo controlled changes in thermal conductivity (Philip et al., 2008) under magnetic fields. The purpose of this experiment is to investigate thermal transport in ferrofluids. A test apparatus was designed and the thermal resistance of a commercially available ferromagnetic fluid within a test cell was measured as a function of the applied magnetic field.

Processing of Bulk MgB2 Superconductors for Application in Fault Current Limiters

2016 ◽  
Vol 856 ◽  
pp. 32-37
Author(s):  
Tatiana Prikhna ◽  
Vladimir Sokolovsky ◽  
Victor Meerovich ◽  
Michael Eisterer ◽  
Athanasios G. Mamalis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Critical Current Density ◽  
Applied Magnetic Field ◽  
Ac Losses ◽  
Fault Current ◽  
Technology Process ◽  
Fault Current Limiters ◽  
Material Porosity ◽  
Rate Of Response

Fault current limiters (FCL) require superconducting (SC) materials which can provide a definite rate of response to a fault event resulting in the SC – normal state reversible transition. The main characteristics determined the material suitability are the critical current density, jc, thermal conductivity and capacity which are strongly determined by manufacturing technology, in particular, of MgB2. In the paper we estimate the jc of bulk MgB2 samples by the vibrating magnetometer and inductive, contactless transformer, method using ring samples. The bulk MgB2 samples were produced under 30 MPa (hot pressing) and 2 GPa (quasihydrostatic pressing) at 800-1050 оС from different initial ingredients (Mg and B or MgB2 with and without additions). It is shown that the technology process and initial ingredients strongly influence the distribution of boron-and oxygen-enriched nanosized inhomogenities in MgB2 matrix, connectivity between SC grains, material porosity and, as result, the SC properties. The transformer method gives the jc in the range from 1.6·104 up to 6.3·104 A/cm2 at about 4 K while using magnetometer measurements the jc is estimated from 2.24·105 up to 5.1·105 A/cm2 at 10 K in self-magnetic fields. The contradictions in the jc estimated by different methods can be explained by instability of the SC state of MgB2, caused by variation of the applied magnetic field. Using the transformer method AC losses per a cycle before quenching for the best materials were estimated around 0.75-1 J/cm3, while the power of losses was about 200 W. The FCL model with rings cut out from SC MgB2 materials prepared using various technologies demonstrated that MgB2 is a promising material for application in inductive FCLs.

scholarly journals MAGNETIC FIELD INDUCED GAP AND KINK BEHAVIOR OF THERMAL CONDUCTIVITY

2002 ◽  
Vol 16 (04) ◽  
pp. 107-116 ◽  
Author(s):  
E. J. FERRER ◽  
V. P. GUSYNIN ◽  
V. DE LA INCERA
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
External Magnetic Field ◽  
Critical Field ◽  
Applied Magnetic Field ◽  
Interaction Model ◽  
Critical Magnetic Field ◽  
Landau Levels

The thermal conductivity of a quasiparticle (QP) system described by a relativistic four-fermion interaction model in the presence of an external magnetic field is calculated. It is shown that, for narrow widths of quasiparticles, the thermal conductivity, as a function of the applied magnetic field, exhibits a kink behavior at a critical field B c ~ T2. The kink is due to the opening of a gap in the QP spectrum at a critical magnetic field B c and to the enhancement of the transitions between the zeroth and first Landau levels. Possible applications of the results are discussed.

Pressure Tuning of Magnetism and Drastic Increment of Thermal Conductivity under Applied Magnetic Field in HgCr 2 S 4

2016 ◽  
Vol 33 (6) ◽  
pp. 067501
Author(s):  
Chuan-Chuan Gu ◽  
Xu-Liang Chen ◽  
Chen Shen ◽  
Lang-Sheng Ling ◽  
Li Pi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Applied Magnetic Field ◽  
Pressure Tuning
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