Analysis of the Factors Affecting the Realization of Lambda Transition Temperature of 4He

2011 ◽  
Vol 18 (1) ◽  
pp. 13-24 ◽  
Author(s):  
L. Yin ◽  
P. Lin ◽  
J. Zhao ◽  
X. Qi
Keyword(s):  
Transition Temperature ◽  
Heat Flow ◽  
Depression Effect ◽  
Resistance Thermometer ◽  
Factors Affecting ◽  
Heat Flows ◽  
Flow Through ◽  
Lambda Transition ◽  
The Stability ◽  
Temperature Plateau

Analysis of the Factors Affecting the Realization of Lambda Transition Temperature of 4He Owing to the dramatic change in the thermal conductivity of 4He when its temperature crosses the transition of superfluid (HeI) and normalfluid (HeII), a sealed-cell with a capillary is used to realize the lambda transition temperature, Tλ. A small heat flow is controlled through the capillary of the sealed-cell so as to realize the coexistence of HeI and HeII and maintain the stay of HeI/HeII interface in the capillary. A stable and flat lambda transition temperature "plateau" is obtained. Because there is a depression effect of Tλ caused by the heat flow through the capillary, a series of heat flows and several temperature plateaus are made and an extrapolation is applied to determine Tλ with zero heat flow. A rhodium-iron resistance thermometer with series number A34 (RIRT A34) has been used in 24 Tλ -realization experiments to derive Tλ with a standard deviation of 0.022mK, which proves the stability and reproducibility of Tλ.

Chemical boundary layers of the mantle and core

1989 ◽  
Vol 328 (1599) ◽  
pp. 441-442 ◽  
Keyword(s):  
Boundary Layer ◽  
Heat Flow ◽  
Large Scale ◽  
High Heat ◽  
Mantle Flow ◽  
Sufficient Information ◽  
Deep Interior ◽  
Gravimetric Data ◽  
Flow Through ◽  
The Stability

There is now sufficient information from seismological mapping of the Earth’s deep interior to draw some preliminary conclusions regarding nature of large-scale mantle flow. This paper examines three features of mantle heterogeneity. Seismological studies confirm the existence of a thick (more than 300 km) thermal boundary layer (tbl) beneath the ancient cratonic nuclei. Petrological and gravimetric data imply that the continental tbl is stabilized against convective disruption by a buoyant, viscous, chemical boundary layer (cbl) depleted in Fe and A1 relative to Mg. Geothermal constraints require high heat production within the cbl and low heat flow through its base, indicating that the cbl has been recharged by large-ion lithophile (lil) elements after primary depletion events. Formation of this continental tectosphere cannot be simple conductive cooling, as in the oceans, but must involve several stages characterized by different timescales, terminating with crustal stabilization; the advective thickening of a basalt-depleted, LiL-rich cbl in episodes of compressive orogenesis (e.g. supercontinent assembly) may be an important mechanism for tectospheric consolidation. The stability and low basal heat flow of the cratonic cbl are evidence that the positions of the continents through time are coupled to the upward flow of material from the deep mantle.

Geothermal measurements in five small lakes of northwest Ontario

1976 ◽  
Vol 13 (7) ◽  
pp. 987-992 ◽  
Author(s):  
R. G. Allis ◽  
G. D. Garland
Keyword(s):  
Heat Flow ◽  
High Heat ◽  
Canadian Shield ◽  
Small Lakes ◽  
Bottom Water Temperature ◽  
Heat Flows ◽  
Small Correction ◽  
Flow Through ◽  
Gradient Measurements ◽  
Lateral Temperature

The heat flow through the floors of five small lakes of known thermal history on the Canadian Shield was measured with a modified Bullard probe. A small correction for seasonal bottom water temperature variations was applied to temperature gradient measurements, and the heat flows are corrected for glaciation, lateral temperature gradients, sedimentation rates, and lateral thermal conductivity changes. Four lakes have an average heat flow of 49 ± 4 mW/m2 (1.2 ± 0.1 μcal/cm2 s). A high heat flow in the fifth lake is thought due to unusual refraction effects. The heat generation–heat flux combination yields a point that falls near accepted lines for the Canadian Shield.

scholarly journals A MELTING POINT FOR THE BIREFRINGENT COMPONENT OF MUSCLE

1966 ◽  
Vol 30 (3) ◽  
pp. 453-464 ◽  
Author(s):  
John F. Aronson
Keyword(s):  
Transition Temperature ◽  
Ionic Strength ◽  
Striated Muscle ◽  
Species Difference ◽  
Psoas Muscle ◽  
Rabbit Muscle ◽  
Large Decrease ◽  
Factors Affecting ◽  
Wide Ph Range ◽  
The Stability

The A filament of the striated muscle sarcomere is an ordered aggregate of one or a few species of proteins. Ordering of these filaments into a parallel array is the basis of birefringence in the A region, and loss of birefringence is therefore a measure of decreased order. Heating caused a large decrease in the birefringence of glycerinated rabbit psoas muscle fibers over a narrow temperature range (∼3°C) and a large decrease in both the birefringence and optical density of the A region of Drosophila melanogaster fibrils. These changes were interpreted as a loss of A filament structure and were used to define a transition temperature (Ttr) as a measure of the stability of the A region. Since the transition temperature was sensitive to pH, ionic strength, and urea, solvent conditions which often affect protein structure, it is an experimentally useful indicator for factors affecting the structure of the A filament. Fibers from glycerinated frog muscle were less stable over a wide pH range than fibers from glycerinated rabbit muscle, a fact which demonstrates a species difference in structure. Glycerinated rabbit fibrils heated to 70°C shortened to about 40% of their initial length. The extent of shortening was not correlated with the loss of birefringence, and phase-contrast microscopy showed that this shortening occurred in the I region as well as in the A region. This response may be useful for studying the I filament and actin in much the same way that the decrease in birefringence was used for studying the A filament and myosin. The observations presented show that some properties of muscle proteins can be studied essentially in situ without the necessity of first dispersing the structure in solutions of high or low ionic strength.

scholarly journals Determining the heat flow through the cabinet walls of household refrigerating appliances

2021 ◽  
Vol 121 ◽  
pp. 235-242
Author(s):  
Andreas Paul ◽  
Elmar Baumhögger ◽  
Andreas Elsner ◽  
Lukas Moczarski ◽  
Michael Reineke ◽  
...  
Keyword(s):  
Heat Flow ◽  
Flow Through

scholarly journals Numerical simulation of periodic MHD casson nanofluid flow through porous stretching sheet

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Abdullah Al-Mamun ◽  
S. M. Arifuzzaman ◽  
Sk. Reza-E-Rabbi ◽  
Umme Sara Alam ◽  
Saiful Islam ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Lewis Number ◽  
Stability And Convergence ◽  
Radiation Absorption ◽  
Physical Parameters ◽  
Theoretical Idea ◽  
Prostate Cancer Therapy ◽  
Flow Through ◽  
Explicit Finite Difference ◽  
The Stability

AbstractThe perspective of this paper is to characterize a Casson type of Non-Newtonian fluid flow through heat as well as mass conduction towards a stretching surface with thermophoresis and radiation absorption impacts in association with periodic hydromagnetic effect. Here heat absorption is also integrated with the heat absorbing parameter. A time dependent fundamental set of equations, i.e. momentum, energy and concentration have been established to discuss the fluid flow system. Explicit finite difference technique is occupied here by executing a procedure in Compaq Visual Fortran 6.6a to elucidate the mathematical model of liquid flow. The stability and convergence inspection has been accomplished. It has observed that the present work converged at, Pr ≥ 0.447 indicates the value of Prandtl number and Le ≥ 0.163 indicates the value of Lewis number. Impact of useful physical parameters has been illustrated graphically on various flow fields. It has inspected that the periodic magnetic field has helped to increase the interaction of the nanoparticles in the velocity field significantly. The field has been depicted in a vibrating form which is also done newly in this work. Subsequently, the Lorentz force has also represented a great impact in the updated visualization (streamlines and isotherms) of the flow field. The respective fields appeared with more wave for the larger values of magnetic parameter. These results help to visualize a theoretical idea of the effect of modern electromagnetic induction use in industry instead of traditional energy sources. Moreover, it has a great application in lung and prostate cancer therapy.

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