scholarly journals Graphene Oxide–Polymer Hydrogel: Wettability and Sound Absorption

2021 ◽  
Author(s):  
A. Khosrozadeh ◽  
R. Rasuli ◽  
H. Hamzeloopak ◽  
Y. Abedini
Keyword(s):  
Graphene Oxide ◽  
Surface Energy ◽  
Sound Absorption ◽  
Absorption Peak ◽  
Polymer Hydrogel ◽  
Sound Absorber ◽  
Attenuation Value ◽  
Hydrogel Polymer

Abstract In this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJm-2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g-1 (for HP) up to 3.246 cm2 g-1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequency according to humidification time.

scholarly journals Wettability and sound absorption of graphene oxide doped polymer hydrogel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Khosrozadeh ◽  
R. Rasuli ◽  
H. Hamzeloopak ◽  
Y. Abedini
Keyword(s):  
Graphene Oxide ◽  
Surface Energy ◽  
Sound Absorption ◽  
Absorption Peak ◽  
Polymer Hydrogel ◽  
Sound Absorber ◽  
Attenuation Value ◽  
Doped Polymer ◽  
Hydrogel Polymer

AbstractIn this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJ m−2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g−1 (for HP) up to 3.246 cm2 g−1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while the nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequencies according to humidification time.

Preliminary Study on Bamboo as Sound Absorber

2014 ◽  
Vol 554 ◽  
pp. 76-80 ◽  
Author(s):  
Fazlin A. Khair ◽  
Azma Putra ◽  
Mohd Jailani Mohd Nor ◽  
Nurul Atiqah ◽  
M.Z. Selamat
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Hollow Structure ◽  
Chemical Substance ◽  
The Body ◽  
Natural Material ◽  
Sound Absorber ◽  
Tube Test ◽  
Average Absorption Coefficient ◽  
Preliminary Study

Synthetic acoustic materials are known for their poisonous chemical substance to the environment and also the particles which are harmful to human health. Research is now directed towards finding an alternative acoustic absorber made from natural materials. This paper presents the utilization of bamboo, a natural material having hollow structure to act as sound absorber. In an impedance tube test, the hollow path is arranged to face the sound incidence. The result reveals that bamboo having length of 2 cm has average absorption coefficient of 0.95 at frequency above 3 kHz. Performance at lower frequencies can be controlled by adding the air gap behind the system. Introduction of microholes along the body shows no significant effect to increase the sound absorption.

The Role of Reduced Graphene Oxide Concentration as Ablated Material on Optical Properties of Graphene Quantum Dots

2019 ◽  
Vol 948 ◽  
pp. 267-273 ◽  
Author(s):  
Fiqhri Heda Murdaka ◽  
Ahmad Kusumaatmaja ◽  
Isnaeni ◽  
Iman Santoso
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Oxide ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Optical Band Gap ◽  
Graphene Quantum Dots ◽  
Absorption Peak ◽  
Oxygen Defect ◽  
Reduced Graphene

We report the synthesize of Graphene Quantum Dots (GQDs) using ablation method with reduced Graphene Oxide (rGO) solution as a starting material. We have varied the concentration of rGO as following: 0.5, 2, 5 mg/ml and then have ablated them using 800 nm Ti-Sapphire femtosecond laser to obtain GQDs. From the UV-Vis data, we observed that the more concentration of rGO is being ablated, the more secondary absorption peak at 255.1 nm appeared. This secondary absorption peak is a characteristic of n-π* bonding due to the presence of oxygen defect which occurs as a result of the interaction between the laser and the water in rGO solution. We conclude that the population of oxigen defect in GQDs is increasing, following the increase of rGO concentration and could alter the optical properties of GQD. On the other hand, using Tauc’s plot, we confirm that the increase of rGO concentration as the ablated material does not alter GQDs optical band gap. However, it will slightly reduce both, direct and indirect Oxygen defect related optical band gap.

scholarly journals Low Frequency Sound Absorption by Optimal Combination Structure of Porous Metal and Microperforated Panel

2019 ◽  
Vol 9 (7) ◽  
pp. 1507 ◽  
Author(s):  
Xinmin Shen ◽  
Panfeng Bai ◽  
Xiaocui Yang ◽  
Xiaonan Zhang ◽  
Sandy To
Keyword(s):  
Finite Element ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Low Frequency ◽  
Porous Metal ◽  
Cuckoo Search ◽  
Element Model ◽  
Frequency Sound ◽  
Sound Absorber ◽  
Standing Wave Tube

The combination structure of a porous metal and microperforated panel was optimized to develop a low frequency sound absorber. Theoretical models were constructed by the transfer matrix method based on the Johnson—Champoux—Allard model and Maa’s theory. Parameter optimizations of the sound absorbers were conducted by Cuckoo search algorithm. The sound absorption coefficients of the combination structures were verified by finite element simulation and validated by standing wave tube measurement. The experimental data was consistent with the theoretical and simulation data, which proved the efficiency, reliability, and accuracy of the constructed theoretical sound absorption model and finite element model. The actual average sound absorption coefficient of the microperforated panel + cavity + porous metal + cavity sound absorber in the 100–1800 Hz range reached 62.9615% and 73.5923%, respectively, when the limited total thickness was 30 mm and 50 mm. The excellent low frequency sound absorbers obtained can be used in the fields of acoustic environmental protection and industrial noise reduction.

Surface Energy Engineered, High-Resolution Micropatterning of Solution-Processed Reduced Graphene Oxide Thin Films

2012 ◽  
Vol 25 (6) ◽  
pp. 894-898 ◽  
Author(s):  
Nam Hee Kim ◽  
Beom Jun Kim ◽  
Yeongun Ko ◽  
Jeong Ho Cho ◽  
Suk Tai Chang
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
High Resolution ◽  
Surface Energy ◽  
Reduced Graphene Oxide ◽  
Oxide Thin Films ◽  
Solution Processed ◽  
Reduced Graphene

A Novel Thermal Insulation, Sound Absorption and Decoration Material

2011 ◽  
Vol 383-390 ◽  
pp. 3922-3928
Author(s):  
H.B. Zhu ◽  
P.M. Wang ◽  
C.S. Wang ◽  
G.T. Yan ◽  
Y.S. Cheng ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Cavity Resonator ◽  
Building Energy ◽  
Short Fiber ◽  
Building Energy Efficiency ◽  
Sound Absorber ◽  
The World ◽  
Novel Material ◽  
Heat Preservation ◽  
High Sound

Both of noise and building energy efficiency are attached importance to in the world. A novel material is developed to control noise, save building energy and decorate for buildings. Porous absorber, cavity resonator resonance sound absorber, film resonance sound absorber, functional absorber and high sound absorber are utilized to improve the sound absorbability. Perlite, Ordinary Portland cement, silicon fume, re-dispersible emulsion powder or emulsion, air-entraining agent, superplasticizer, short fiber and mesh fabrics are used to prepare novel material. Organic silicone waterproof material is used to prevent it from destroying, assist for sound absorbability and decorate for surface. After designing wedge sound absorber by mould, forming cavity resonator resonance sound absorber by air-entraining agent, and controlling compression ratio, diameter of perlite grain and cement dosage, final performances of sound absorbability and heat preservation can meet requirements of ASTM C423-84A and GB/T 20473-2006 respectively.

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