Heat Insulating Materials Thermal Conductivity Determination by Means of Comparison With a Standard Plate of Known Conductivity

2012 ◽  
Author(s):  
Chyouhwu Brian Huang ◽  
Hung-Shyong Chen
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Low Cost ◽  
Testing Machine ◽  
Living Standard ◽  
Energy Prices ◽  
Conductivity Method ◽  
Plate Temperature ◽  
Flow Rates ◽  
Cooling Flow

Due to the soaring energy prices, the cost to maintain a basic living standard has increased, therefore choosing right insulated materials when building a new house/appliance is important. The heat transfer coefficient plays a vital role; therefore, developing an effective, accurate, and low cost testing machine is an important issue. This is also the goal of this research. The testing apparatus developed can be used to measure the thermal conductivity as a basis for the choice of the materials. The heat conduction testing equipment was designed using “the thermal conductivity comparison with a known conductivity” method in addition to the basic heat conduction theory. For the best results, several parameters were used to fine-tune the operating conductions, such as cooling flow rate, heat source temperature, etc. Three types of materials were used as the sample for verifying the accuracy of the developed apparatus: gypsum board, silicon cement and PE polyethylene foam. Four heat sources temperatures were tested: 30°C, 35°C, 40°C, and 45°C. Two cooling flow rates were used: 108 liter/hour and 90 liter/hour. In the end, ANSYS was used to validate the testing results. The testing results show that the measured thermal conductivity is accurate. Equilibrium can be reached faster when testing with high cooling flow rates. The best hot plate temperature is 30°C.

scholarly journals Determination of heavy water by means of a thermal conductivity method

1958 ◽  
Vol 7 (5) ◽  
pp. 301-304 ◽  
Author(s):  
Saburo YANAGISAWA ◽  
Michiharu SEKI ◽  
Yoshikazu WATANABE ◽  
Shigeru NAKAMURA ◽  
Fumio MORIYA
Keyword(s):  
Thermal Conductivity ◽  
Heavy Water ◽  
Conductivity Method

Simultaneous enhancements in the Seebeck coefficient and conductivity of PEDOT:PSS by blending ferroelectric BaTiO3 nanoparticles

2021 ◽  
Author(s):  
Chang'an Li ◽  
Xin Guan ◽  
Shizhong Yue ◽  
Xi Zu Wang ◽  
Jianmin Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Low Cost ◽  
Low Thermal Conductivity ◽  
Low Toxicity ◽  
Batio3 Nanoparticles

Thermoelectric polymers have attracted great attention because of their unique merits including low thermal conductivity, low cost, non- or low toxicity and high mechanical flexibility. However, their thermoelectric properties particularly...

AN EXPLORATION OF THE RELATIONSHIP BETWEEN THE QUALITY OF PUBLIC GOVERNANCE AND INCOME INEQUALITY: A CASE STUDY OF VIETNAM

2021 ◽  
pp. 1-15
Author(s):  
PHUC VAN PHAN
Keyword(s):  
Income Inequality ◽  
Local Governance ◽  
Low Cost ◽  
Generalized Method Of Moments ◽  
Dynamic Panel Data ◽  
Living Standard ◽  
Public Governance ◽  
The Relationship

Public governance and income inequality relationship is complex and debatable. This paper examines the extent to which the quality of local governance affects inequality in Vietnam spanning the 2006–2016 period. I apply a generalized method of moments (GMM) estimators to a dynamic panel data extracted from the Vietnam’s provincial competitiveness index and the Vietnam household living standard surveys. The findings are that there is a positive inequality — corruption link but no statistically significant correlation coefficient between the overall level of governance and income disparity. The study, therefore, suggests that the Vietnamese Government at all levels should consider both more effective legal practices and economic low-cost solutions to mitigate corruption.

scholarly journals Silica Aerogel Monoliths Derived from Silica Hydrosol with Various Surfactants

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3192 ◽  
Author(s):  
Dong Chen ◽  
Xiaodong Wang ◽  
Wenhui Ding ◽  
Wenbing Zou ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Silica Aerogel ◽  
Low Cost ◽  
Ambient Pressure ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Low Thermal Conductivity ◽  
Silica Hydrosol ◽  
High Production Cost

Owing to their ultra-low thermal conductivity, silica aerogels are promising thermal insulators; however, their extensive application is limited by their high production cost. Thus, scientists have started to explore low-cost and easy preparation processes of silica aerogels. In this work, a low-cost method was proposed to prepare silica aerogels with industrial silica hydrosol and a subsequent ambient pressure drying (APD) process. Various surfactants (cationic, amphoteric, or anionic) were added to avoid solvent exchange and surface modification during the APD process. The effects of various surfactants on the microstructure, thermal conductivity, and thermal stability of the silica aerogels were studied. The results showed that the silica aerogels prepared with a cationic or anionic surfactant have better thermal stability than that prepared with an amphoteric surfactant. After being heated at 600 °C, the silica aerogel prepared with a cationic surfactant showed the highest specific surface area of 131 m2∙g−1 and the lowest thermal conductivity of 0.038 W∙m−1∙K−1. The obtained low-cost silica aerogel with low thermal conductivity could be widely applied as a thermal insulator for building and industrial energy-saving applications.

scholarly journals Lattice Boltzmann method simulation of the gas heat conduction of nanoporous material

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3749-3756
Author(s):  
Ya Han ◽  
Shuai Li ◽  
Hai-Dong Liu ◽  
Weipeng Cui
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Size Effects ◽  
Temperature Jump ◽  
Boundary Scattering ◽  
Nanoporous Material ◽  
Boltzmann Method

In order to deeply investigate the gas heat conduction of nanoporous aerogel, a model of gas heat conduction was established based on microstructure of aerogel. Lattice Boltzmann method was used to simulate the temperature distribution and gas thermal conductivity at different size, and the size effects of gas heat conduction have had been obtained under micro-scale conditions. It can be concluded that the temperature jump on the boundary was not obvious and the thermal conductivity remained basically constant when the value of Knudsen number was less than 0.01; as the value of Knudsen number increased from 0.01 to 0.1, there was a clear temperature jump on the boundary and the thermal conductivity tended to decrease and the effect of boundary scattering increased drastically, as the value of Knudsen number was more than 0.1, the temperature jump increased significantly on the boundary, furtherly, the thermal conductivity decreased dramatically, and the size effects were significantly.

scholarly journals Low-Cost Force Sensors Embedded in Physical Human–Machine Interfaces: Concept, Exemplary Realization on Upper-Body Exoskeleton, and Validation

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 505
Author(s):  
Niclas Hoffmann ◽  
Samet Ersoysal ◽  
Gilbert Prokop ◽  
Matthias Hoefer ◽  
Robert Weidner
Keyword(s):  
Low Cost ◽  
Testing Machine ◽  
Measurement Data ◽  
Upper Body ◽  
Testing Environment ◽  
Physical Support ◽  
Pressure Distributions ◽  
Human Machine Interfaces ◽  
Piezoresistive Pressure Sensor ◽  
Material Testing Machine

In modern times, the collaboration between humans and machines increasingly rises, combining their respective benefits. The direct physical support causes interaction forces in human–machine interfaces, whereas their form determines both the effectiveness and comfort of the collaboration. However, their correct detection requires various sensor characteristics and remains challenging. Thus, this paper presents a developed low-cost sensor pad working with a silicone capsule and a piezoresistive pressure sensor. Its measurement accuracy is validated in both an isolated testing environment and a laboratory study with four test subjects (gender-balanced), and an application integrated in interfaces of an active upper-body exoskeleton. In the material-testing machine, it becomes apparent that the sensor pad generally features the capability of reliably determining normal forces on its surface until a certain threshold. This is also proven in the real application, where the measurement data of three sensor pads spatially embedded in the exoskeletal interface are compared to the data of an installed multi-axis load cell and a high-resolution flexible pressure map. Here, the consideration of three sensor pads potentially enables detection of exoskeletal support on the upper arm as well as “poor” fit conditions such as uneven pressure distributions that recommend immediate system adjustments for ergonomic improvements.

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