A LARGE-SCALE THERMAL CONDUCTANCE APPARATUS USED FOR THE TESTING OF BUILDING MATERIALS

1939 ◽  
Vol 17a (8) ◽  
pp. 164-177
Author(s):  
J. D. Babbitt
Keyword(s):  
Thermal Conductivity ◽  
Large Scale ◽  
Building Materials ◽  
Thermal Conductance ◽  
Short Description ◽  
Hot Plate ◽  
Good Agreement

A short description and discussion are given of a thermal conductance apparatus of the guarded hot-box type used by the National Research Laboratories, Ottawa, for the measurement of the thermal conductivity of building materials. Results obtained with this apparatus are compared with hot-plate measurements on the same materials and indicate good agreement between the two methods.

scholarly journals Testing a Gypsum Composite Based on Raw Gypsum with a Direct Admixture of Paraffin and Polymer to Improve Thermal Properties

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3241
Author(s):  
Krzysztof Powała ◽  
Andrzej Obraniak ◽  
Dariusz Heim
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Phase Change ◽  
Large Scale ◽  
Building Materials ◽  
Residential Buildings ◽  
Energy Performance ◽  
Polymer Content ◽  
Volumetric Heat Capacity

The implemented new legal regulations regarding thermal comfort, the energy performance of residential buildings, and proecological requirements require the design of new building materials, the use of which will improve the thermal efficiency of newly built and renovated buildings. Therefore, many companies producing building materials strive to improve the properties of their products by reducing the weight of the materials, increasing their mechanical properties, and improving their insulating properties. Currently, there are solutions in phase-change materials (PCM) production technology, such as microencapsulation, but its application on a large scale is extremely costly. This paper presents a solution to the abovementioned problem through the creation and testing of a composite, i.e., a new mixture of gypsum, paraffin, and polymer, which can be used in the production of plasterboard. The presented solution uses a material (PCM) which improves the thermal properties of the composite by taking advantage of the phase-change phenomenon. The study analyzes the influence of polymer content in the total mass of a composite in relation to its thermal conductivity, volumetric heat capacity, and diffusivity. Based on the results contained in this article, the best solution appears to be a mixture with 0.1% polymer content. It is definitely visible in the tests which use drying, hardening time, and paraffin absorption. It differs slightly from the best result in the thermal conductivity test, while it is comparable in terms of volumetric heat capacity and differs slightly from the best result in the thermal diffusivity test.

Effect of Sidewall Conductance on Nusselt Number for Rayleigh-Bénard Convection: A Semi-Analytical and Experimental Correction

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
U. Madanan ◽  
R. J. Goldstein
Keyword(s):  
Thermal Conductivity ◽  
Nusselt Number ◽  
Analytical Model ◽  
Thermal Conductance ◽  
Bénard Convection ◽  
Benard Convection ◽  
Extended Surfaces ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard ◽  
Good Agreement

Abstract The effect of sidewall conductance on Nusselt number for the Rayleigh-Bénard convection is examined by performing nearly identical sets of experiments with sidewalls made of three different materials. These experimental results are utilized to extrapolate and estimate the Nusselt number for an ideal zero-thermal-conductivity sidewall case, which is the case when the sidewalls are perfectly insulating. A semi-analytical model is proposed, based on the concept of extended surfaces, to compute the discrepancy in Nusselt number caused by the presence of finite thermal conductance of the sidewalls. The predictions obtained using this model are found to be in good agreement with the corresponding experimentally determined values.

Thermal Conductivity of Graphene Nanoribbons: Effect of the Edges and Ribbon Width

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Paul Plachinda ◽  
David Evans ◽  
Raj Solanki
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Graphene Nanoribbons ◽  
Thermal Conductance ◽  
Ribbon Width ◽  
Edge Termination ◽  
Relative Contribution ◽  
Edge Roughness ◽  
Edge Scattering ◽  
Good Agreement

We have calculated thermal conductance of graphene nanoribbons (GNRs) and their dependence on the type of ribbon edge termination (zigzag or armchair) and the width of the ribbon, which ranges from 50 Å to 50 μm. Our model incorporates the effect of edge roughness and includes edge roughness correlation functions for both types of termination. The dependence of thermal conductance on the width of the ribbons and relative contribution of different scattering mechanisms are also analyzed by means of the Green’s function approach to the edge scattering. High temperature thermal conductance of the nanoribbons was found to be 0.15 nW/K and 0.18 nW/K (corresponding to thermal conductivity, 4641 and 5266 W/mK, respectively, for 10 μm long GNRs) which is in a good agreement with the experimental results.

scholarly journals A Novel Miniature and Selective CMOS Gas Sensor for Gas Mixture Analysis—Part 2: Emphasis on Physical Aspects

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 587
Author(s):  
Moshe Avraham ◽  
Sara Stolyarova ◽  
Tanya Blank ◽  
Sharon Bar-Lev ◽  
Gady Golan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Gas Sensor ◽  
Catalytic Reaction ◽  
Analytical Models ◽  
Gas Mixture ◽  
Thermal Sensor ◽  
Catalytic Layer ◽  
Sensing Element ◽  
Hot Plate ◽  
Good Agreement

This is a second part of the paper presenting a miniature, combustion-type gas sensor (dubbed GMOS) based on a novel thermal sensor (dubbed TMOS). The TMOS is a micromachined CMOS-SOI transistor, which acts as the sensing element and is integrated with a catalytic reaction plate, where ignition of the gas takes place. Part 1 focused on the chemical and technological aspects of the sensor. In part 2, the emphasis is on the physical aspects of the reaction micro-hot plate on which the catalytic layer is deposited. The three main challenges in designing the hot plate are addressed: (i) How to design a hot plate operating in air, with a low thermal conductivity; (ii) how to measure the temperature of the hot plate during operation; (iii) how to reduce the total consumed power during operation. Reported simulated as well as analytical models and measured results are in good agreement.

Improvements to the Guarded Hot Plate Apparatus to Determine Thermal Conductivity

2017 ◽  
Author(s):  
Gabriel Souza ◽  
Luís Felipe dos Santos Carollo ◽  
Sandro Metrevelle Marcondes de Lima e Silva
Keyword(s):  
Thermal Conductivity ◽  
Hot Plate ◽  
Guarded Hot Plate ◽  
Plate Apparatus

Characterization of Interconnect Defects Using Scanning Thermal Conductivity Microscopy

2004 ◽  
Author(s):  
H.W. Ho ◽  
J.C.H. Phang ◽  
A. Altes ◽  
L.J. Balk
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Large Scale

Abstract In this paper, scanning thermal conductivity microscopy is used to characterize interconnect defects due to electromigration. Similar features are observed both in the temperature and thermal conductivity micrographs. The key advantage of the thermal conductivity mode is that specimen bias is not required. This is an important advantage for the characterization of defects in large scale integrated circuits. The thermal conductivity micrographs of extrusion, exposed and subsurface voids are presented and compared with the corresponding topography and temperature micrographs.

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