Preparation of pore-controllable zirconium carbide ceramics with tunable mechanical strength, thermal conductivity and sound absorption coefficient

2020 ◽  
Vol 46 (11) ◽  
pp. 19609-19616 ◽  
Author(s):  
Ningning Yan ◽  
Qiangang Fu ◽  
Yuyu Zhang ◽  
Kun Li ◽  
Wei Xie ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Absorption Coefficient ◽  
Mechanical Strength ◽  
Sound Absorption ◽  
Zirconium Carbide ◽  
Sound Absorption Coefficient ◽  
Carbide Ceramics

Effect of Nanocellulose on Acoustical and Thermal Insulation Properties of Silicone Rubber Composite

2019 ◽  
Vol 964 ◽  
pp. 156-160 ◽  
Author(s):  
Mohammad Farid ◽  
Agung Purniawan ◽  
Diah Susanti ◽  
Amaliya Rasyida ◽  
Henry Yulianto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Absorption Coefficient ◽  
Silicone Rubber ◽  
Sound Absorption ◽  
Wide Band ◽  
Sound Absorption Coefficient ◽  
Empty Fruit Bunch ◽  
A Value ◽  
Rubber Composite ◽  
The Matrix

Nanocellulose composites are very potential to be applied as automotive component materials.The purpose of this research is to analyze the influence of nanocellulose fraction of the silicon rubber composite material to morphology, sound absorption coefficient, density, thermal stability, and thermal conductivity. The nanocellulose of the composites were isolated from oil palm empty fruit bunch, while the matrix was silicone rubber. Tests conducted in this research included sound absorption coefficient, SEM, TGA, density, and thermal conductivity. Sound absorption coefficient had a value between 0,33 to 0.42 for a frequency of 500 Hz to 4000 Hz. This sound absorption coefficient had a wide band sound absorption tendency and was developed for sound absorption material of mufflers.

Studies of the Influence of Graphite on the Physical Mechanical and Thermal Properties of Polyurethane Foams for Construction Applications

2021 ◽  
Vol 887 ◽  
pp. 399-405
Author(s):  
L.N. Shafigullin ◽  
N.V. Romanova ◽  
G.R. Shafigullina
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Polyurethane Foams ◽  
Onset Temperature ◽  
Sound Absorption Coefficient ◽  
Expandable Graphite ◽  
Mechanical And Thermal Properties ◽  
Pu Foam

The paper shows the applicability of expandable graphite METOPAC EG 350-50 (80) in a rigid PU foam system as a substance that reduces the flammability (flame retardant) and improves the usability. The studies of the physical mechanical and thermal properties of PU foam with a higher graphite content revealed a higher normal sound absorption coefficient; insignificant influence on the thermal conductivity; a higher decomposition onset temperature; more difficult ignition. PU foam sample with a ratio of 15 graphite weight fractions to 100 polyol weight fractions has the highest physical mechanical and thermal properties, and, as compared to the starting PU foam, it features an increase in normal sound absorption coefficient by an average of 3 times; a decrease in the thermal conductivity by 8 %; an increase in the decomposition onset temperature by 6.7 °С. Therefore, the modification of PU foam with expandable graphite makes it possible not only to develop hardly combustible polyurethanes but also to improve its physical mechanical and thermal properties.

scholarly journals Experimental and Modelling Studies on Thermal Insulation and Sound Absorption Properties of Cross-Laid Nonwoven Fabrics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tao Yang ◽  
Lizhu Hu ◽  
Xiaoman Xiong ◽  
Michal Petrů ◽  
Sundaramoorthy Palanisamy ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Absorption Coefficient ◽  
Thermal Insulation ◽  
Sound Absorption ◽  
Nonwoven Fabric ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Nonwoven Fabrics ◽  
Significant Difference ◽  
Modelling Studies

Abstract Nonwoven fabrics are widely used for thermal insulation and sound absorption purpose in construction and automobile fields. It is essential to investigate their thermal conductivity and sound absorption coefficient. Five cross-laid nonwoven fabrics are measured on the Alambeta device and Brüel & Kjær impedance tube. Bogaty and Bhattacharyya models are selected to predict the thermal conductivity, and Voronina and Miki models are used to predict the sound absorption coefficient. The predicted thermal conductivity shows a significant difference compared with the measured values. It is concluded that Bogaty and Bhattacharyya models are not suitable for high porous nonwoven fabric. In addition, the results of Voronina and Miki models for sound absorption prediction are acceptable, but Voronina model shows lower mean prediction error compared with Miki model. The results indicate that Voronina model can be used to predict the sound absorption of cross-laid nonwoven fabric.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals Air permeability and sound absorption coefficient changes from ultrasonic treatment in a cross section of Malas (Homalium foetidum)

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Chun-Won Kang ◽  
Eun-Suk Jang ◽  
Nam-Ho Lee ◽  
Sang-Sik Jang ◽  
Min Lee
Keyword(s):  
Absorption Coefficient ◽  
Ultrasonic Treatment ◽  
Sound Absorption ◽  
Gas Permeability ◽  
Treated Wood ◽  
Untreated Wood ◽  
Sound Absorption Coefficient ◽  
Permeability Constant ◽  
Average Value ◽  
Permeability Increase

AbstractWe investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average sound absorption coefficients in the range of 50 to 6.4 kHz and NRC (noise reduction coefficient: average value of sound absorption coefficient value at 250, 500, 1000, and 2000 Hz) of untreated Malas. Those values were 0.23 (SD 0.02) and 0.13 (SD 0.01), respectively, while those of ultrasonic-treated Malas were 0.28 (SD 0.02) and 0.14 (SD 0.02), a 19.74% increase in average sound absorption coefficient.

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

2018 ◽  
Vol 89 (16) ◽  
pp. 3342-3361 ◽  
Author(s):  
Tao Yang ◽  
Ferina Saati ◽  
Kirill V Horoshenkov ◽  
Xiaoman Xiong ◽  
Kai Yang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Absorption Coefficient ◽  
Empirical Model ◽  
Surface Impedance ◽  
Sound Absorption ◽  
Low Frequency ◽  
Accurate Method ◽  
Small Error ◽  
Sound Absorption Coefficient ◽  
Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

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