On the thermal structure and stability of configurations with heat diffusion and a gain-loss function. II - Application to the interstellar medium

1993 ◽  
Vol 412 ◽  
pp. 625 ◽  
Author(s):  
Antonio Parravano ◽  
Miguel H. Ibanez ◽  
Cesar A. Mendoza
Keyword(s):  
Interstellar Medium ◽  
Loss Function ◽  
Thermal Structure ◽  
Heat Diffusion ◽  
Structure And Stability ◽  
Gain Loss

Measurement of the thermal conductivity of thin layers using a scanning thermal microscope

2001 ◽  
Vol 16 (9) ◽  
pp. 2530-2543 ◽  
Author(s):  
Erwin R. Meinders
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Thermal Structure ◽  
Thin Layers ◽  
Heat Diffusion ◽  
Sputter Deposited ◽  
Relative Differences ◽  
Conductivity Of Thin Films ◽  
Change Material

A scanning thermal microscope (SThM) was used to measure the thermal conductivity of thin sputter-deposited films in the thickness range of 10 nm–10 μm. The SThM method is based on a heated tip that is scanned across the surface of a sample. The heat flowing into the sample is correlated to the local thermal conductivity of the sample. Issues like the contact force, the surface roughness of the sample, and tip degradation, which determine to a great extent the contact area between tip and surface, and thus the heat flow to the sample, are addressed in the paper. A calibration curve was measured from known reference materials to quantify the sample heat flow. This calibration was used to determine the effective thermal conductivity of samples. Further, the heat diffusion through a layered sample due to a surface heat source was analyzed with an analytical and numerical model. Measurements were performed with films of aluminum, ZnS–SiO2, and GeSbTe phase change material of variable thickness and sputter-deposited on substrates of glass, silicon, or polycarbonate. It is shown in the paper that the SThM is a suitable tool to visualize relative differences in thermal structure of nanometer resolution. Determination of the thermal conductivity of thin layers is possible for layers in the micrometer range. It is concluded that the SThM is not sensitive enough to measure accurately the thermal conductivity of thin films in the nanometer range. Suggestions for improvement of the SThM method are given.

scholarly journals Critical Quality Source Diagnosis for Dam Concrete Construction Based on Quality Gain - loss Function

2014 ◽  
Vol 7 (2) ◽  
pp. 137-151 ◽  
Author(s):  
Bo Wang ◽  
◽  
Zhiyong Li ◽  
Junyan Gao ◽  
Heap Vaso ◽  
...  
Keyword(s):  
Loss Function ◽  
Concrete Construction ◽  
Dam Concrete ◽  
Gain Loss ◽  
Source Diagnosis

Quality Gain-Loss Function and Its Empirical Analysis in Dam Concrete Construction

2020 ◽  
Vol 104 (sp1) ◽  
Author(s):  
Bo Wang ◽  
Hougui Zhou ◽  
Zhiyong Li ◽  
Tianyu Fan ◽  
Xiangtian Nie
Keyword(s):  
Empirical Analysis ◽  
Loss Function ◽  
Concrete Construction ◽  
Dam Concrete ◽  
Gain Loss

scholarly journals Synthetic observations of turbulent flows in diffuse multiphase interstellar medium

2006 ◽  
Vol 2 (S237) ◽  
pp. 499-499
Author(s):  
Masako Yamada ◽  
H. Koyama ◽  
K. Omukai ◽  
S. Inutsuka
Keyword(s):  
Interstellar Medium ◽  
Turbulent Flows ◽  
Thermal Structure ◽  
Line Emission ◽  
High Ratio ◽  
Excitation Energies ◽  
Interstellar Clouds ◽  
Hydrodynamic Simulations ◽  
Non Local ◽  
Multi Phase

AbstractWe examined observational characteristics of multi-phase turbulent flows in the diffuse interstellar medium (ISM) by calculating atomic and molecular carbon lines. Radiation field maps of C+, C0, and CO line emissions were generated by calculating the non-local thermodynamic equilibrium (nonLTE) level populations and high resolution hydrodynamic simulations of diffuse ISM. By analyzing synthetic line emission, we found a high ratio between the lines of high- and low-excitation energies in the diffuse multi-phase interstellar medium. Our results shows that simultaneous observations of the lines of warm- and cold-gas tracers will be useful in examining the thermal structure, and hence the origin of diffuse interstellar clouds.

Heat thermal structure in the interfacial boundary layer measured in an open tank of water in turbulent free convection

1977 ◽  
Vol 83 (2) ◽  
pp. 311-335 ◽  
Author(s):  
Kristina B. Katsaros ◽  
W. Timothy Liu ◽  
Joost A. Businger ◽  
James E. Tillman
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Standard Deviation ◽  
Theoretical Calculations ◽  
Thermal Structure ◽  
The Body ◽  
Heat Diffusion ◽  
Return Flow ◽  
Experimental Conditions ◽  
Heat Diffusion Equation

The thermal structure in the boundary layer and its relation to the heat flux from the cooling and evaporating surface of a deep tank of water are investigated. When a deep layer of water in contact with still air above loses heat to the air, the cooled water in a region just under the surface converges along lines and then plunges down in sheets. These sheets of falling water dissipate as they move into the body of the water, which is in turbulent motion. The vertical profiles of the horizontally averaged temperature and its standard deviation agree fairly closely with theoretical profiles based on time averages of the solution to the heat diffusion equation. The differences between observed and thus predicted profile shapes are consistent with the expected effects of the falling cold thermals and the warm return flow, which are neglected in the theories. The profiles of the standard deviation have large values up to the interface and lie between predictions based on boundary conditions of constant surface temperature and constant heat flux, in keeping with the experimental conditions.The relation between the net heat flux and the temperature difference across the boundary layer is given in non-dimensional form by N = 0[sdot ]156R0[sdot ]33, which is in good agreement with the asymptotic similarity prediction N [vprop ] R1/3 but lower than theoretical calculations of the upper bound of N vs. R.

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