scholarly journals Enhancing egg cartons’ sound absorption coefficient with recycled materials

2017 ◽  
Vol 24 (2) ◽  
pp. 115-131 ◽  
Author(s):  
Prasasto Satwiko ◽  
Verza Dillano Gharata ◽  
Herybert Setyabudi ◽  
Fefen Suhedi
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
Noise Source ◽  
Absorption Measurement ◽  
Sound Absorption Coefficient ◽  
Recycled Materials ◽  
Human Voice ◽  
Reduction Coefficient ◽  
High Sound

Egg cartons have popularly been used as sound absorbers because they are inexpensive, easy to install and easily available. However, acoustic experts have demonstrated that egg cartons are bad sound absorbers. This study developed Enhanced Egg Carton – Dry and Enhanced Egg Carton – Wet using additional recycled materials (shredded rice straw paper, textile waste, 2-cm cut rice straws) to improve the cartons’ sound absorption coefficient while retaining their original advantages. Enhanced Egg Carton – Dry and Enhanced Egg Carton – Wet were tested based on the ASTM C423-02 method of sound absorption measurement. Enhanced Egg Carton – Dry has a noise reduction coefficient of 0.6 and a sound absorption average of 0.59, while Enhanced Egg Carton – Wet has a noise reduction coefficient of 0.54 and sound absorption average of 0.54. The maximum sound absorption coefficients of Enhanced Egg Carton – Dry and Enhanced Egg Carton – Wet are, respectively, 0.77 at 500 Hz and 0.67 at 630 Hz. Enhanced Egg Carton – Dry has a sound absorption coefficient ⩾0.5, between 315 and 2500 Hz, which makes it able to absorb sound energy of the lower to upper mid-range frequencies. With their high sound absorptivity at mid-range frequencies, Enhanced Egg Carton – Dry and Enhanced Egg Carton – Wet are suitable for mosques and auditoriums, where the human voice is the dominant noise source and where an inexpensive sound absorber is needed. The production of Enhanced Egg Carton – Dry and Enhanced Egg Carton – Wet is so simple that users can do it themselves using basic home tools.

scholarly journals The Sound Absorption Coefficient of Railway Concrete Sleepers Containing Palm Oil Fuel Ash (POFA) As a Cement Replacement Material

2021 ◽  
Vol 2129 (1) ◽  
pp. 012032
Author(s):  
Nurfarhanna Ahmad Sulaiman ◽  
Suraya Hani Adnan ◽  
Abdul Hadi Izaan ◽  
Mohamad Hairi Osman ◽  
Mohamad Luthfi Ahmad Jeni ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Palm Oil ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Palm Oil Fuel Ash ◽  
Noise And Vibration ◽  
Fuel Ash ◽  
Reduction Coefficient ◽  
Oil Fuel

Abstract Major noise and vibration during train operation can cause disturbance to the surrounding. One of the methods to reduce this disturbance are by installing concrete sleepers. The use of railway concrete sleepers may be a high potential to reduce the noise and vibration. To produce concrete sleepers cement usage will be used with greater volume. Approximately 100 million tons of Palm Oil Fuel Ash (POFA) was disposed to the landfill currently. POFA contains high silica content and porous particles which indicated its pozzolanic properties and sound absorption characteristics. Therefore, this study was to determine the sound absorption coefficient of railway concrete sleepers containing POFA as a cement replacement material. Concrete sleepers with a strength grade of 55 and a w/c ratio of 0.35 were prepared in this study. Three design mixes with 0% (control), 20%, and 40% of POFA tested by using an impedance tube test at 28 days of curing age. The results show, the sound absorption coefficient and noise reduction coefficient increases as the percentage of POFA increases. The best performance was obtained by concrete sleepers containing 40% of POFA, with a recorded sound absorption coefficient of 0.10 for low frequency and 0.44 for high frequency. Meanwhile, the noise reduction coefficient recorded was 0.33, which reduce 32% of noise compared to OPC.

Effect of microfiber layers on acoustical absorptive properties of nonwoven fabrics

2019 ◽  
Vol 50 (3) ◽  
pp. 312-332 ◽  
Author(s):  
Gajanan Bhat ◽  
Magdi El Messiry
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
Decisive Role ◽  
Mineral Wool ◽  
Acoustic Energy ◽  
Sound Absorption Coefficient ◽  
Nonwoven Materials ◽  
Reduction Coefficient ◽  
Melt Blown Nonwoven

There are several types of sound absorptive materials, such as natural and synthetic fibers, acoustic mineral wool, acoustic polyester panels, acoustic foam, cotton batts, that reduce the acoustic energy of a sound wave as the wave passes through. In this work, the use of nonwoven materials made of cotton, polyester, and polypropylene fibers for the development of sound absorptive nonwoven materials has been investigated. Samples of different materials (cotton, cotton/polyester blend, polyester fibers needle punched, and polypropylene melt blown nonwoven) and multilayer structures were tested on the designed impedance tube. Acoustic absorption properties of the fiber assemblies were studied in the frequency region of 100–1500 Hz. The values of sound absorption coefficient for different samples indicated that polypropylene microfiber melt blown nonwoven sample displayed a good sound absorption behavior in the entire frequency range. The use of multilayer samples improves the sound absorption coefficient with the condition that one of the layers is a thin melt blown nonwoven layer. The formation of nonwoven absorbent material consisted of hybrid layers, significantly reduces the resultant average sound absorption coefficient, especially when the upper layer is made from finer fibers of melt blown nonwoven of low air permeability value, and in this case the improvement reaches 50%. The use of melt blown layers of fine fibers values of noise reduction coefficient may reach 0.8. The multilayer nonwoven sound absorber design should take into consideration specific noise reduction coefficient values, not the absolute ones, particularly when the weight of the absorber is playing a decisive role.

Sound Absorption of Laminated Biopolymer Foam and Epoxy Foam

2013 ◽  
Vol 594-595 ◽  
pp. 291-295 ◽  
Author(s):  
Noor Quratul Aine Adnan ◽  
Anika Zafiah M. Rus
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Vegetable Oil ◽  
Sound Absorption ◽  
Acoustic Property ◽  
Sound Absorption Coefficient ◽  
Behavior Theory ◽  
Tube Test ◽  
Epoxy Foam ◽  
Reduction Coefficient

Biopolymer foam was prepared based on vegetable oil and Polyol Flexible (Epoxy) with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI) as laminated foam. The acoustic property of biopolymer foam was examined by impedance tube test according to ASTM E-1050 of sound absorption coefficient (α). From the result obtain, sample D and sample C are the best result of sound absorption coefficient (α) for biopolymer foam and epoxy foam with the value are 0.867 and 0.817 respectively. By using the sound behavior theory, when the thickness is increase the sound absorption is also increase as same as in this study. The noise reduction coefficient (NRC) of sample D is 38.26% while for sample C is 37.42%.

Development of Kenaf Nonwoven as Automotive Noise Absorption

2019 ◽  
Vol 892 ◽  
pp. 101-105
Author(s):  
Siti Nor Hawanis Husain ◽  
Nur Aiman Abdul Razak ◽  
Azrin Hani Abdul Rashid ◽  
Musli Nizam Bin Yahya ◽  
Nurul Zakiah Zamri Tan ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
Negative Relationship ◽  
Sound Absorption Coefficient ◽  
Function Technique ◽  
Impedance Tube ◽  
Number Of Layers ◽  
Reduction Coefficient ◽  
Sound Reduction

Getting rid of unwanted noise in car compartment is necessary and really significant measure for automotive makers. This research was directed to produce nonwoven material from Kenaf fiber using the needle-punching machine and the ability of the produced material to absorb sound will be tested. The performance in sound absorption of the sample was analyzed by the sound absorption coefficient (SAC) and noise reduction coefficient (NRC) using the impedance tube test referring to ASTM E1050-98. The sound absorption frequencies were evaluated utilizing the two-microphone transfer function technique in the impedance tube that has a 100 mm diameter for low frequency and 28 mm for high frequency, 0 Hz to 4000 Hz respectively. The physical examination also was executed according to ASTM D1772 to determine the density and the thickness of each sample. The parameter verified in this research is the number of layers to form the samples and it also were compared with the commercial products. As the outcome of this research, the sound absorption coefficient (SAC) showed that the sound reduction coefficient value was increased as the number of layers of the sample increase. In summation, the result also proved that the denser the samples, the higher the absorption coefficient value. On the other hand, for the noise reduction coefficient (NRC), overall result showed slight differences between each sample. The result is due to the rating is an average, two materials with the same rating might not perform the same. Referring to the previous research, the sample with higher areal density is dependable for higher sound reduction and there is a negative relationship between area density and bulk density of needle-punched nonwoven and sound reduction. With the rise in the number of density of nonwoven fabric, the sound reduction through the fabric increases at first but after the maximum it remains almost unaffected.

The Acoustic Insulation Property of a New Non-Woven Material

2011 ◽  
Vol 194-196 ◽  
pp. 471-475 ◽  
Author(s):  
Jin Jing Chen ◽  
Zheng Guo
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Nonwoven Material ◽  
Sound Absorption Coefficient ◽  
Flame Resistance ◽  
Hydrophobic Property ◽  
Insulation Property ◽  
Acoustic Insulation ◽  
High Sound ◽  
Different Thickness

The acoustic insulation and hydrophobic properties of a new non-woven material were analyzed and discussed in this paper. The new non-woven material absorbs sound energy to transfer into heat energy by friction between viscosity of air near fiber and fiber. The acoustic insulation properties of the new non-woven material, polyurethane foam and felt were measured. With the same thickness and half weight of felt, the sound absorption coefficient of non-woven was 20~30% higher than felt. Further more, with the same weight of felt, the sound absorption coefficient of non-woven was50~60% higher than felt. However, the sound absorption coefficients of non-woven materials with different thickness and weight were also discussed. The amount of the sound absorption coefficient gradient increased with the increase of thickness and frequency. Comparing the existing sound absorption materials, the new non-woven material has high sound absorption, light weight, hydrophobic property, workability, and flame resistance property. The non-woven material can improved thermal insulation and sound absorption by combining conventional non-woven with aluminum evaporated film.So the new nonwoven material has been widely applied in industries to reduce noises, especially in the car.

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.

Preparation and Sound Absorption Coefficient Test of Aluminum Foam with CaO Granules Infiltrating Agent

2018 ◽  
Vol 933 ◽  
pp. 55-60
Author(s):  
Yong Zhang ◽  
Zong Min Chen ◽  
Zhao Jun Wang ◽  
Jing Hui Liu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Aluminum Foam ◽  
Low Frequency ◽  
Processing Parameters ◽  
Sound Absorption Coefficient ◽  
Pressure Infiltration ◽  
Pure Alcohol ◽  
Infiltration Pressure ◽  
High Sound

Three kinds of aluminum foam of different pore sizes were prepared with a tailor-made low-pressure infiltration device. CaO granules in three sizes (0.45~0.71mm,0.71~090mm and 1.25~1.60mm) were selected as infiltrating agents. The processing parameters were as follows: granules preheat temperature of 700 °C,infiltration pressure of 0.04 MPa and aluminum liquid temperature of 720 °C. In order to improve the removal performance and porosity, mixture of CaO powder of finer than 300 mesh and pure alcohol was mixed uniformly with granules, which made the slurry-coating granules conformal contacts rather than point contacts as in the traditional infiltration method. The testing results show that among all aluminum foam specimens tested with transfer function methods, two kinds have high sound absorption coefficient in low frequency (250~1600Hz).

Sound Absorption Properties of Fiber and Porous Materials

2005 ◽  
Vol 475-479 ◽  
pp. 2687-2690 ◽  
Author(s):  
Bo Young Hur ◽  
Bu Keoun Park ◽  
Dong-In Ha ◽  
Yong Su Um
Keyword(s):  
Absorption Coefficient ◽  
Porous Materials ◽  
Sound Absorption ◽  
Absorption Rate ◽  
Metal Foam ◽  
Acoustic Property ◽  
Glass Wool ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Reduction Coefficient

The porous materials, such as glass wool or foam, are generally used to attenuate noise. The most fundamental acoustic property of these porous materials is their sound absorption coefficient. The purpose of this paper is sintered fiber and porous materials sound absorption properties investigated. Sound absorption properties of sintered Al fiber has over 0.7 of sound absorption coefficient with 800-2000Hz frequency for 0.6 relative density and 10mm thickness. NRC (noise reduction coefficient) is 0.73. Metal foam have good sound absorption rate at 2000 ~ 4000Hz.

Fabrication and Sound Absorption Properties of Porous Fe0.2(Co20Ni80)0.8 Alloy Microfibers

2012 ◽  
Vol 538-541 ◽  
pp. 2220-2223
Author(s):  
Xiang Qian Shen ◽  
Hong Bo Liu ◽  
Qing Rong Liang ◽  
Xin Chun Yang
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Transformation Process ◽  
Sound Absorption Coefficient ◽  
Wave Tube ◽  
Absorption Properties ◽  
Thick Sample ◽  
Noise Absorption ◽  
Reduction Coefficient ◽  
Standing Wave Tube

The porous nanocrystalline Fe0.2(Co20Ni80)0.8 alloy microfibers with diameters of 2-4 μm have been prepared by the citrate-gel and phase transformation process. The sound absorption coefficient for microfibers samples is measured by the standing wave tube method and it is is over 0.8 for the 15 mm thick sample at the frequency range of 2300-6000 Hz, which is extended to 600-6300 Hz for the 40 mm thick sample. The band width with the sound absorption coefficient above 0.6 is wider than 4300 Hz for the 15 mm thick sample and 5800 Hz for the 40 mm thick sample. For the 40 mm thick sample, the maximum absorption coefficient, noise absorption coefficient, noise reduction coefficient and half-width of the absorption peak are 0.99, 0.59, 0.64 and 5828 Hz, respectively. These microfibers are promising advanced acoustic absorbers.

scholarly journals Sound-Absorption Coefficient of Bark-Based Insulation Panels

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1012 ◽  
Author(s):  
Eugenia Mariana Tudor ◽  
Anna Dettendorfer ◽  
Günther Kain ◽  
Marius Catalin Barbu ◽  
Roman Réh ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
Residential Buildings ◽  
Coarse Grained ◽  
Sound Absorption Coefficient ◽  
Sound Insulation ◽  
Formaldehyde Resin ◽  
Frequency Interval ◽  
Spruce Bark

The objective of this study was to investigate the sound absorption coefficient of bark-based insulation panels made of softwood barks Spruce (Picea abies (L.) H. Karst.) and Larch (Larix decidua Mill.) by means of impedance tube, with a frequency range between 125 and 4000 Hz. The highest efficiency of sound absorption was recorded for spruce bark-based insulation boards bonded with urea-formaldehyde resin, at a level of 1000 and 2000 Hz. The potential of noise reduction of larch bark-based panels glued with tannin-based adhesive covers the same frequency interval. The experimental results show that softwood bark, an underrated material, can substitute expensive materials that involve more grey energy in sound insulation applications. Compared with wood-based composites, the engineered spruce bark (with coarse-grained and fine-grained particles) can absorb the sound even better than MDF, particleboard or OSB. Therefore, the sound absorption coefficient values strengthen the application of insulation panels based on tree bark as structural elements for the noise reduction in residential buildings, and concurrently they open the new ways for a deeper research in this field.

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