scholarly journals Sound absorption characteristics of KGM-based aerogel

2020 ◽  
Vol 15 (3) ◽  
pp. 450-457
Author(s):  
Yixin Wang ◽  
Fei Xiang ◽  
Wei Wang ◽  
Weiling Wang ◽  
Yuehong Su ◽  
...  

Abstract This study presents the preparation and property characterization of biomass aerogels as sound absorption materials. Biomasses were chosen to prepare aerogels through the freeze-drying method. Results indicated that four components may have different effects on the aerogel pore structure, and the aerogel formula was thus optimized to reach the best sound absorption. Within the experimental range, biomass aerogel with the optimized formula had an average sound efficiency 0.352, density 0.047 g/cm3 and porosity 94.46 ± 0.04%. It shows better sound absorption performance than traditional sound absorption cotton. These results demonstrate the high sound absorption potential of biomass aerogels for building applications.

2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kusaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to a possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.


Nanoscale ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 2289-2298 ◽  
Author(s):  
Leitao Cao ◽  
Yang Si ◽  
Yuanyuan Wu ◽  
Xueqin Wang ◽  
Jianyong Yu ◽  
...  

Robust functional nanofibrous aerogels were designed by inserting lashing-structured scaffolds through a freeze-drying method.


2020 ◽  
Vol 128 (7) ◽  
pp. 387-394
Author(s):  
Guo-Rui LI ◽  
Chen-Hui LI ◽  
Jiang-An LIU ◽  
Yang ZOU ◽  
Liang HU ◽  
...  

2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kussaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.


2021 ◽  
Vol 11 (23) ◽  
pp. 11573
Author(s):  
Jeongyeon Choi ◽  
Heekyung Jeon

This study focused on the manufacturing of functional superabsorbent sponges using natural polymers. An alginate/CMC-embedded dextran hybrid dual-layer formulation was prepared using the freeze-drying method. The physical properties of the formulation were characterized using a field emission scanning electron microscope and a universal testing machine, and the swelling ratio was calculated. Cell viability assays were performed using keratinocytes (HaCaT cells). The results showed that this formulation can absorb a large amount of moisture and provide morphological stability through its tensile strength and uniform porosity, and this was verified by its biocompatibility. We believe that in the future, by combining this novel hybrid dual-layer superabsorbent sponge with antibacterial agents with excellent porosity, it would serve as a medical material for producing bandages that can absorb blood and body fluids, feminine hygiene products, and functional antibacterial masks.


2014 ◽  
Vol 1626 ◽  
Author(s):  
Changfeng Chen ◽  
Li Liu ◽  
Qiong Wang ◽  
Tao Huang ◽  
Yue`e Fang

ABSTRACTThe present investigation involves the synthesis of chitosan based composite sponges in view of their applications in wound dressing, antibacterial and haemostatic. A facile CO2 bubbles template freeze-drying method was developed for the fabrication of macroporous chitosan- poly(vinyl alcohol) (PVA) composite sponges with a typical porosity of 50% and pore size of 100-300 µm. The composite sponges show a high water absorption rate up to 60 times of its weight and a water vapor transmission rate of 30 ∼ 70g/m2 • h. Effects of the content of cross-linking agent and PVA on mechanical properties and moisture permeability were examined. Improved strength and flexibility of the chitosan sponges were observed with the presence of PVA. Further, the antibacterial and haemostatic activities have been demonstrated. The Chitosan/PVA sponges of high liquid absorption, appropriate moisture permeability, excellent antimicrobial and haemostatic activities have a great potential for wound dressing applications.


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