scholarly journals Measuring thermal conductivity of soils under laboratory conditions.

1969 ◽  
Vol 17 (1) ◽  
pp. 71-79
Author(s):  
A.I. Golovanov
Keyword(s):  
Thermal Conductivity ◽  
Flow Velocity ◽  
Soil Sample ◽  
Water Flow ◽  
Coarse Sand ◽  
Conductivity Measurements ◽  
Soil Layers ◽  
The Real ◽  
Real Flow

Experiments were made to determine the influence of size of soil sample, convection and water flow on the determination of thermal conductivity of soils using a thin needle (0.05 cm radius, 8.5 cm in length) as the heating element and copper cylinders for sample containers. For measurements during a period of 100 seconds the diameter of the sample must be at least 4 cm and to avoid any influence of convection measurements should not exceed 100 seconds. When heating elements are placed horizontally to measure simultaneously the thermal conductivity of different soil layers they should be placed at least 10 cm apart. Thermal conductivity measurements could be used to determine flow velocities of water in coarse sand samples provided that the real flow velocity was highev than 0.35 cm/ min. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Determination of lattice defects in carbon fibers by means of thermal-conductivity measurements

1991 ◽  
Vol 44 (5) ◽  
pp. 2142-2148 ◽  
Author(s):  
B. Nysten ◽  
J.-P. Issi ◽  
R. Barton ◽  
D. R. Boyington ◽  
J. G. Lavin
Keyword(s):  
Thermal Conductivity ◽  
Carbon Fibers ◽  
Lattice Defects ◽  
Conductivity Measurements

Determination of mesopore size of aerogels from thermal conductivity measurements

2002 ◽  
Vol 298 (2-3) ◽  
pp. 287-292 ◽  
Author(s):  
Ok-Joo Lee ◽  
Kun-Hong Lee ◽  
Tae Jin Yim ◽  
Sun Young Kim ◽  
Ki-Pung Yoo
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurements

scholarly journals A211 Determination of water flow velocity around Ram Flameholder by PIV

1997 ◽  
Vol 17 (Supplement2) ◽  
pp. 51-54
Author(s):  
Jacky GUEZET ◽  
Mitsuo GOMI ◽  
Shigemi SHINDO ◽  
Kazuo SUZUKI
Keyword(s):  
Flow Velocity ◽  
Water Flow ◽  
Water Flow Velocity

Thermal Conductivity Measurements on Polycrystalline Silicon Microbridges Using the 3ω Technique

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Patrick E. Hopkins ◽  
Leslie M. Phinney
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Polycrystalline Silicon ◽  
Microelectromechanical Systems ◽  
Experimental Methods ◽  
Electrical Contacts ◽  
Conductivity Measurements ◽  
Advantages And Disadvantages ◽  
3Ω Technique

The thermal performance of microelectromechanical systems devices is governed by the structure and composition of the constituent materials as well as the geometrical design. With the continued reduction in the characteristic sizes of these devices, experimental determination of the thermal properties becomes more difficult. In this study, the thermal conductivity of polycrystalline silicon (polysilicon) microbridges are measured with the transient 3ω technique and compared with measurements on the same structures using a steady state Joule heating technique. The microbridges with lengths from 200 μm to 500 μm were designed and fabricated using the Sandia National Laboratories SUMMiT V™ surface micromachining process. The advantages and disadvantages of the two experimental methods are examined for suspended microbridge geometries. The differences between the two measurements, which arise from the geometry of the test structures and electrical contacts, are explained by bond pad heating and thermal resistance effects.

scholarly journals Dimensional characterization of heat flux in aquifers with horizontal water flow. Velocity estimation from temperature-depth profiles

2021 ◽  
Author(s):  
José Antonio Valera ◽  
Francisco Alhama
Keyword(s):  
Flow Velocity ◽  
Water Flow ◽  
Transfer Problem ◽  
Direct Determination ◽  
Velocity Estimation ◽  
Water Flow Velocity ◽  
Dimensionless Groups ◽  
Selection Of

From the dimensionless governing equations obtained through an adequate selection of dependent and independent dimensionless variables, and the use of spatial discrimination, the dimensionless groups that govern the solution patterns of the heat transfer problem in aquifers with horizontal flow velocity are determined. As a boundary condition on the surface, the cases of constant and harmonic temperature are studied. The emergence of a characteristic length that, in its dimensionless form, depends on the deduced groups, allows the direct determination of the water flow from experimental measurements of the temperature profiles in the classical form of the inverse problem.

scholarly journals Thermal Conductivity Measurements on Polysilicon Microbridges Using the 3-Omega Technique

2008 ◽  
Author(s):  
Patrick E. Hopkins ◽  
Leslie M. Phinney
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Polycrystalline Silicon ◽  
Microelectromechanical Systems ◽  
Boundary Resistance ◽  
Mems Devices ◽  
Conductivity Measurements ◽  
3 Omega ◽  
3Ω Technique

The thermal properties of microelectromechanical systems (MEMS) devices are governed by the structure and composition of the constituent materials as well as the geometrical design. With the continued reduction of the characteristic sizes of these devices, experimental determination of the thermal properties becomes more difficult. In this study, the thermal conductivity of polycrystalline silicon (polysilicon) microbridges are measured with the transient 3ω technique and compared to measurements on the same structures using a steady state joule heating technique. The microbridges with lengths from 200 microns to 500 microns were designed and fabricated using the Sandia National Laboratories SUMMiT™ V surface micromachining process. The differences between the two measurements, which arise from the geometry of the test structures, are explained by bond pad heating and thermal boundary resistance effects.

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