scholarly journals Thermal impedance at the interface of contacting bodies: 1-D examples solved by semi-derivatives

2012 ◽  
Vol 16 (2) ◽  
pp. 623-627 ◽  
Author(s):  
Jordan Hristov
Keyword(s):  
Heat Conduction ◽  
Fractional Calculus ◽  
Half Time ◽  
Thermal Impedance ◽  
Entire Domain ◽  
Transient Thermal ◽  
Two Bodies

Simple 1-D semi-infinite heat conduction problems enable to demonstrate the potential of the fractional calculus in determination of transient thermal impedances of two bodies with different initial temperatures contacting at the interface ( x = 0 ) at t = 0 . The approach is purely analytic and uses only semi-derivatives (half-time) and semi-integrals in the Riemann-Liouville sense. The example solved clearly reveals that the fractional calculus is more effective in calculation the thermal resistances than the entire domain solutions.

scholarly journals Thermal impedance estimations by semi-derivatives and semi-integrals: 1-D semi-infinite cases

2013 ◽  
Vol 17 (2) ◽  
pp. 581-589 ◽  
Author(s):  
Jordan Hristov ◽  
Ganaoui El
Keyword(s):  
Heat Conduction ◽  
Fractional Calculus ◽  
Boundary Conditions ◽  
Half Time ◽  
Thermal Impedance ◽  
Entire Domain ◽  
Various Boundary Conditions ◽  
Transient Thermal

Simple 1-D semi-infinite heat conduction problems enable to demonstrate the potential of the fractional calculus in determination of transient thermal impedances under various boundary conditions imposed at the interface (x=0). The approach is purely analytic and very effective because it uses only simple semi-derivatives (half-time) and semi-integrals and avoids development of entire domain solutions. 0x=

A study of the diffusion analogy technique for the photoelastic determination of transient thermal stresses

1988 ◽  
Vol 23 (1) ◽  
pp. 33-45
Author(s):  
P Stanley ◽  
Y J Yip
Keyword(s):  
Heat Conduction ◽  
Temperature Distribution ◽  
Isotropic Material ◽  
Heat Conduction Equation ◽  
Thermal Stresses ◽  
Conduction Equation ◽  
Formal Similarity ◽  
Photoelastic Study ◽  
Transient Thermal

The formal similarity between the equation governing the diffusion of a substance through a “porous” isotropic material and the heat conduction equation for the temperature distribution in an isotropic homogeneous solid is examined, and its use as a basis for the photoelastic study of transient thermal stresses is explored.

Determination of Myocardial FFA Elimination Rates by Functional Images of Uncorrected Half-Time Values

1984 ◽  
Vol 23 (06) ◽  
pp. 277-282 ◽  
Author(s):  
A. Van Lingen ◽  
G. Westera ◽  
M. van ◽  
W. Den Hollander ◽  
E. E. Van der Wall ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Regions Of Interest ◽  
Heptadecanoic Acid ◽  
Half Time ◽  
Alternative Method ◽  
Functional Images ◽  
Functional Image ◽  
Back Ground ◽  
Objective Determination

SummaryThis paper presents an alternative method of demarcating regions of in terest over the myocardium after ad ministration of 123I-heptadecanoic acid to patients with coronary artery disea se. In a matrix of 32 × 32 pixels the elimination rates of the radioactivity, which are not corrected for back ground activity, are visualized per pixel in a functional image. The func tional image showed areas in the myocardium with high values of uncorrected elimination rates. These areas corresponded with the tracer defects on the scintigram. Corrected elimination rates obtained from re gions of interest of functional images were comparable with those of scinti grams. Thus based on functional im ages of uncorrected elimination rates a reliable, objective determination of regions of interest over normal and abnormal myocardium can be made.

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals Some Applications of the Wright Function in Continuum Physics: A Survey

Mathematics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 198
Author(s):  
Yuriy Povstenko
Keyword(s):  
Heat Conduction ◽  
Fractional Calculus ◽  
Exponential Function ◽  
Nonlocal Elasticity ◽  
Bessel Functions ◽  
Wright Function ◽  
Mainardi Function ◽  
Integral Relations

The Wright function is a generalization of the exponential function and the Bessel functions. Integral relations between the Mittag–Leffler functions and the Wright function are presented. The applications of the Wright function and the Mainardi function to description of diffusion, heat conduction, thermal and diffusive stresses, and nonlocal elasticity in the framework of fractional calculus are discussed.

Simultaneous Determination of Steady Temperatures and Heat Fluxes on Surfaces of Three Dimensional Objects Using FEM

2001 ◽  
Author(s):  
Brian H. Dennis ◽  
George S. Dulikravich
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Conduction ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Multiply Connected ◽  
Three Dimensional Objects ◽  
Solid Objects ◽  
System Solution

Abstract A finite element method (FEM) formulation is presented for the prediction of unknown steady boundary conditions in heat conduction on multiply connected three-dimensional solid objects. The present FEM formulation is capable of determining temperatures and heat fluxes on the boundaries where such quantities are unknown or inaccessible, provided such quantities are sufficiently over-specified on other boundaries. Details of the discretization, linear system solution techniques, regularization, and sample results for 3-D problems are presented.

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