Green Materials for Sound Absorption

2017 ◽  
Vol 729 ◽  
pp. 63-67 ◽  
Author(s):  
Amelia Trematerra ◽  
Ilaria Lombardi
Keyword(s):  
Sound Absorption ◽  
Flow Resistance ◽  
Noise Pollution ◽  
Acoustic Measurements ◽  
Frequency Range ◽  
Synthetic Materials ◽  
Green Materials ◽  
Acoustic Comfort ◽  
Useful Life ◽  
Materials Used

Green materials are becoming a valid alternative to traditional synthetic materials. The green materials can be used in different fields of the building constructions. The green materials are sustainable, infact the at the end of its useful life they can be dispersed into the environment without damaging it. So the green material can be used in improving the acoustic comfort inside environment, as well as to mitigate noise pollution. In this paper are reported the acoustic measurements of the properties of green materials. The absorption coefficient of samples of the materials, were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube (tube of ”Kundt”); the flow resistance was also measured. Furthermore the problems about the realization of sound-absorbing panels composed of green materials, used for the acoustic correction of classroom, were discussed.

The acoustic characterization of green materials

2017 ◽  
Vol 24 (2) ◽  
pp. 101-113 ◽  
Author(s):  
Gino Iannace
Keyword(s):  
Plant Litter ◽  
Wood Chips ◽  
Natural Fibres ◽  
Acoustic Absorption ◽  
Acoustic Measurements ◽  
Frequency Range ◽  
Synthetic Materials ◽  
Green Materials ◽  
Acoustic Characterization

Natural materials are a valid alternative to traditional synthetic materials in the fields of acoustic treatments and energy saving. Natural fibres have been used to produce sound-absorbing panels. This article reports the acoustical characterization of the following natural fibres: straw, hay, plant litter and different sized wood chips. The acoustic measurements were carried out with an impedance tube. The acoustic absorption values were measured in a frequency range between 200 and 2000 Hz.

USE OF CORK SHEETS FOR ROOM ACOUSTIC CORRECTION

2020 ◽  
Vol 15 (2) ◽  
pp. 45-55
Author(s):  
Gino Iannace ◽  
Giuseppe Ciaburro ◽  
Luigi Guerriero ◽  
Amelia Trematerra
Keyword(s):  
Sound Absorption ◽  
Rigid Wall ◽  
Virtual Model ◽  
Rear Wall ◽  
Acoustic Characteristics ◽  
Architectural Acoustics ◽  
Acoustic Comfort ◽  
Useful Life ◽  
Correction System

ABSTRACT Cork is a sustainable material and at the end of its useful life it can be disposed of into the environment without causing damage. This paper analyzes an acoustic correction system made of cork sheets mounted at an opportune distance from the walls inside a room. The cork sheets have a thickness equal to 1.5 mm. The sound absorption coefficients of the cork sheets were initially evaluated by mounting samples inside an impedance tube, then creating a back cavity at a suitable distance from a rigid wall. The distances considered were: 3, 5, 10 and 15 cm. A room used as an office with a volume of about 90 m3 and plastered walls was considered as a case-study. In this type of environment, suitable acoustic comfort conditions are required. The acoustic characteristics were analyzed through a virtual model with an architectural acoustics software in an empty room and then with the introduction of sound-absorbing cork sheets. Measurements of the acoustic characteristics of the empty room were taken and subsequently with the walls lined with cork panels mounted at a distance of 3.0 cm from the rigid rear wall. A configuration was analyzed, in line with what was carried out in the numerical model, covering a surface of 5m2 of the room. The results of the numerical simulations as well as the experimental measurements are discussed.

scholarly journals Sound Absorption Coefficient of Different Green Materials Polymer on Noise Reduction

2020 ◽  
Vol 9 (3) ◽  
pp. 2773-2777
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
New Technologies ◽  
Raw Materials ◽  
Agricultural Waste ◽  
Noise Pollution ◽  
Sound Absorption Coefficient ◽  
Absorption Coefficients ◽  
Green Materials

One of the sources of noise pollution to environment is from the consumption of electrical and mechanical appliances usage at home and industries. Growth development and advancement of heavy equipment in construction work further emphasize the necessity used of new technologies for noise reduction. The best technique of control or reducing of noise is by using the materials that can absorb the noise by materials itself. Potential materials from agricultural waste as sound absorber were identified. There are two main objectives in this study; First is to produce acoustic absorber by using natural materials. Second is to identify their sound absorption coefficients. The samples were fabricated using the raw materials from banana stem, grass, palm oil leaves and lemongrass mixed with binding agents of polyurethane and hardener to the ratio of 1:4. The diameters of the samples consist of 28mm and 100mm and the thickness is 10mm. The samples sound absorption coefficients were measured according to standards ASTM E1050-98 / ISO 105342-2 (Impedance tube method). Sound absorption coefficient of the materials depends on frequencies choose. The frequencies values used in this study were in the range from 500Hz to 4500Hz. Material made from grass have a higher average sound absorption coefficient value which is 0.553. All tested samples also can be categories under class D type of materials based on sound absorption coefficient value.

Correction of Acoustics in Historic Opera Theatres with the Use of Schroeder Diffuser

2012 ◽  
Vol 37 (3) ◽  
pp. 349-354 ◽  
Author(s):  
Tadeusz Kamisiński
Keyword(s):  
Sound Absorption ◽  
Similar Type ◽  
Wall Surface ◽  
Acoustic Measurements ◽  
Frequency Range ◽  
Rear Wall ◽  
Acoustic Parameters ◽  
High Frequencies ◽  
Strength Factor ◽  
Echo Effect

Abstract The paper deals with the problem of acoustic correction in historic opera theatres with the auditorium layout in the form of a horseshoe with deep underbalcony cavities limited with a semicircular wall surface. Both geometry of the cavities and excessive sound absorption determine acoustic phenomena registered in this area of the hall. The problem has been observed in the Theatre of Opera and Ballet in Lviv, Ukraine, where acoustic tests were carried out, simulation calculations performed, and finally a diffusion panel worked out designed for the rear wall of the underbalcony space. Acoustic measurements carried out after installation of the diffusers revealed favourable changes in the sound strength factor G within the range of medium and high frequencies in the underbalcony and auditorium centre area. By replacing textile tapestry with diffusion panels, a significant reduction of sound absorption was achieved for the frequency range above 1 kHz and an increase of uniformity of acoustic parameters registered in the hall. The method presented in the paper can be applied in historic halls of the similar type as well as contemporary rooms where there is a need for correction of acoustic flaws related to sound focusing or the echo effect.

Acoustic Properties of Cork Sheets

2017 ◽  
Vol 744 ◽  
pp. 66-70 ◽  
Author(s):  
Amelia Trematerra ◽  
Ilaria Lombardi
Keyword(s):  
Absorption Coefficient ◽  
Rigid Wall ◽  
Acoustic Properties ◽  
Frequency Range ◽  
Impedance Tube ◽  
Green Material ◽  
Sustainable Material ◽  
Synthetic Materials ◽  
Green Materials

Green materials can be considered as a valid alternative to traditional synthetic materials. The cork is a green material, in fact it is a sustainable material. Cork can be used to improve the acoustics inside buildings. The systems used consist of cork sheets mounted at a distance onto a rigid wall, with the thickness of the sheet being 1.5 mm. The distances from the rigid wall considered are equal to 5 cm, 10 cm and 15 cm. The absorption coefficient of the sample was measured in the frequency range from 100 Hz to 2000 Hz with an impedance tube.

Effect of Bulk Density on the Acoustic Performance of Thermally Bonded Nonwovens

2015 ◽  
Vol 10 (3) ◽  
pp. 155892501501000 ◽  
Author(s):  
Wenbin Zhu ◽  
Vidya Nandikolla ◽  
Brian George
Keyword(s):  
Absorption Coefficient ◽  
Bulk Density ◽  
Sound Absorption ◽  
Flow Resistance ◽  
Raw Materials ◽  
Sound Absorption Coefficient ◽  
Acoustic Performance ◽  
Materials Used ◽  
Lower Bulk Density ◽  
Blend Ratios

The effect of different fiber blend ratios and bulk densities at similar thicknesses on air permeability and sound absorption coefficient was investigated. The raw materials used were cotton, polyester, and bi-component fibers to make acoustic nonwovens through the air-laid and thermal bonding processes. A uniform thermal-conductivity box was designed in order to make thermally bonded nonwovens with fixed thicknesses. The experimental results depict that the air flow resistance of three-layer nonwoven was 0.565 kPa&mitdott;s/m, which was about four times greater than one-layer of 0.12 kPa·s/m. Sound absorption coefficient of 20% polyester-60% cotton-20% bicomponent nonwoven with lower bulk density was greater than the 60% polyester-20% cotton-20% bicomponent nonwoven. The sound absorption coefficient varied based on which fabric side faced the testing apparatus.

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 Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

scholarly journals Pneumatic transport of bulk materials in construction of composite floating docks

2021 ◽  
pp. 1-14
Author(s):  
A.S. Rashkovskyi ◽  
A.V. Shchedrolosiev ◽  
V.M. Neiman ◽  
O.Y. Kanash
Keyword(s):  
Wear Resistance ◽  
Transport System ◽  
Flow Rate ◽  
Pneumatic Transport ◽  
Pipe Diameter ◽  
Bulk Materials ◽  
Useful Life ◽  
Materials Used ◽  
Theoretical Results

Investigations of pneumatic transport of bulk materials used in shipbuilding have carried out. Their abrasiveness, wear of straight and curved sections of pipelines were investigated. Theoretically, the dependences of the amount of wear on various factors were defined: abrasiveness and concentration of transported particles, flow rate, pipe diameter and wear resistance of its material, structural and operational features of the transport system, etc. Formulas for determining the maximum useful life of straight and curved sections of pipelines are obtained. Theoretical results confirmed experimentally.

A case study of noise pollution levels during the restrictions period due to COVID-19.

2021 ◽  
Vol 263 (6) ◽  
pp. 206-214
Author(s):  
David Montes-González ◽  
Juan Miguel Barrigón-Morillas ◽  
Ana Cristina Bejarano-Quintas ◽  
Manuel Parejo-Pizarro ◽  
Guillermo Rey-Gozalo ◽  
...  
Keyword(s):  
Noise Pollution ◽  
Urban Environments ◽  
Control Measures ◽  
Acoustic Measurements ◽  
Pollution Levels ◽  
The World ◽  
The Impact ◽  
The City

The pandemic of coronavirus disease (COVID-19) led to the need for drastic control measures around the world to reduce the impact on the health of the population. The confinement of people in their homes resulted in a significant reduction in human activity at every level (economic, social, industrial, etc.), which was reflected in a decrease in environmental pollution levels. Studying the evolution of parameters, such as the level of environmental noise caused by vehicle traffic in urban environments, makes it possible to assess the impact of this type of measure. This paper presents a case study of the acoustic situation in Cáceres (Spain) during the restriction period by means of long-term acoustic measurements at various points of the city.

Sign in / Sign up

Export Citation Format

Share Document