Influence of High Doping of TiO2 of Polymeric Foam for Acoustic Study

2013 ◽  
Vol 594-595 ◽  
pp. 755-759
Author(s):  
Anika Zafiah M. Rus ◽  
M.A. Bainun Akmal ◽  
N.N. Mat Hassan
Keyword(s):  
Titanium Dioxide ◽  
High Frequency ◽  
Sound Absorption ◽  
Absorption Property ◽  
Polymer Foam ◽  
Polymeric Foam ◽  
Acoustic Study ◽  
Frequency Level ◽  
Reduction Coefficient ◽  
Coefficient Method

Titanium dioxide represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. The purpose of this study is to determine sound absorption property of polymer foam of high doping of Titanium Dioxide (TiO2) which are 20%, 40%, 60%, 80% and 100%. The acoustic study of the samples was measured by using impedance tube test according to the ASTM E-1050 to determined sound absorption coefficient (α) and noise reduction coefficient method (NRC). The highest α is 0.999 observed from the polymer foam doped with 60% of TiO2 at high frequency level of 4000 Hz. Meanwhile, the highest doping of TiO2 polymer foam shows remarkable characteristic of low level frequency absorption at 2000 Hz. Thus, different percentage of TiO2 doped in polymer foam can be used successfully to alter the characteristic of sound absorption property in a systematic way according to the request application.

Influence of Multilayer Textile Biopolymer Foam Doped with Titanium Dioxide for Sound Absorption Materials

2013 ◽  
Vol 594-595 ◽  
pp. 750-754 ◽  
Author(s):  
Anika Zafiah M. Rus ◽  
Nik M. H. Normunira ◽  
Rahimah Abd Rahim
Keyword(s):  
Titanium Dioxide ◽  
Sound Absorption ◽  
Fiber Diameter ◽  
Low Frequency ◽  
Polyester Fabric ◽  
Fiber Density ◽  
Fiber Properties ◽  
Acoustic Study ◽  
Number Of Layers ◽  
Frequency Level

Biopolymer foam was prepared by the reaction of bio-monomer based on vegetable oil with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI) and titanium dioxide (TiO2). The acoustic study of biopolymer foam with 2.5% TiO2 loading was examined by impedance tube test according to the ASTM E-1050 and laminated with three types of textile such as polyester, cotton and single knitted jersey. It was revealed that the thicker the fabric the higher the sound absorption coefficient (α) at low frequency level. The higher the number of layers or thickness of the fabric, the sound absorption through the fabric increases at low frequency but after the maximum it remains almost unaltered. Three layer of cotton fabric gives maximum α approximately equal to 0.578 which is 1.472mm thickness at low frequency level of 1000-2000Hz and single knitted jersey gives maximum α at 3th layer. Meanwhile , the α of biopolymer foam with 2.5% TiO2 loading laminated with polyester fabric approximately equal to 1 at lower frequency level of 1000-2000Hz with lower thickness that is 0.668mm. Polyester fabric with lowest thickness shows better α at lower frequency level due to the structure of the fabric. The relationships among the fiber properties such as fiber density, fiber diameter, fibrous material layer were considered as a factor that influences the sound absorption property.

Utilization of Treated Red Meranti Wood Dust as Polymer Foam Composite for Acoustic Study

2013 ◽  
Vol 594-595 ◽  
pp. 760-764 ◽  
Author(s):  
Shafizah Sa'adon ◽  
Anika Zafiah M. Rus
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Wood Dust ◽  
Polymer Foam ◽  
Tube Test ◽  
Acoustic Study ◽  
Foam Composite ◽  
Absorbing Materials ◽  
Scanning Electron

A Red Meranti Wood Dust (RMD) act as a filler for polymer foam composite has been investigated and proved to have ability to absorb sound. In this study, treatment of wood dust with and without acid hydrolysis named as WDB and WDA respectively was use as filler. This study was developed to compare the ability of sound absorption based on treated filler and particle size of wood dust. By choosing the size of 355 μm, three different percentage has been selected which is 10%, 15% and 20% for both conditions. These samples has been tested by using Impedance Tube test according to ASTM E-1050 for sound absorption coefficient, α measurement and Scanning Electron Microscopy (SEM) for determine the porosity for each samples. 10% loaded of WDB as filler gives highest sound absorption coefficient of 0.999 at 4015.63 Hz. Meanwhile for 20% loaded of WDA gives 0.997 at 3228.13 Hz. When comparing the sound absorption coefficient for both sounds absorbing materials, WDB-polymer foam composite RMD showed higher value of sound absorption coefficient, α at higher frequency as compared to WDA-polymer foam composite.

Acoustic Study Based on Sustainable Green Polymer Treated with H2O

2013 ◽  
Vol 748 ◽  
pp. 281-285 ◽  
Author(s):  
Nik Normunira Mat Hassan ◽  
Anika Zafiah M. Rus ◽  
S. Nurulsaidatulsyida ◽  
Siti Rahmah Mohid
Keyword(s):  
Cell Size ◽  
Morphological Study ◽  
Average Pore Size ◽  
Acoustic Property ◽  
Low Frequency ◽  
Polymer Foam ◽  
Average Pore ◽  
Acoustic Study ◽  
Frequency Level ◽  
Green Polymer

Green polymer foam was prepared by the reaction of green monomer based on vegetable oil with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI) and distilled water (H2O). The morphological study of green polymer foam was examined by Scanning Electron Microscope (SEM) and acoustic property by means of H2O composition ratio equivalent to weight of polyol. It was found that the cell size of green polymer foam has significantly increment as well as H2O loading increased. Increasing of H2O more than 50% equivalent to weight of polyol shows nonuniform pore distribution, large average pore size and smallest number of pore. Furthermore, the cell size of neat green polymer foam gives 400μm up to 1833.3μm with high loading of H2O. In addition, the cell size of green polymer foam influences by the increasing amount of H2O loading and enhanced the sound absorption property at low frequency level.

Influences of Thickness and Fabric for Sound Absorption of Biopolymer Composite

2013 ◽  
Vol 393 ◽  
pp. 102-107 ◽  
Author(s):  
Nik Normunira Mat Hassan ◽  
Anika Zafiah Mohd Rus
Keyword(s):  
Sound Absorption ◽  
Fiber Diameter ◽  
Polyester Fabric ◽  
Medium Frequency ◽  
Fiber Density ◽  
Fiber Properties ◽  
Tube Test ◽  
Acoustic Study ◽  
Number Of Layers ◽  
Frequency Level

Biopolymer foam was prepared by the reaction of bio-monomer based on vegetable oil with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI). The acoustic study of biopolymer foam was examined by impedance tube test according to the ASTM E-1050 and laminated with three types of textile such as polyester, cotton and single knitted jersey. It was revealed that the thicker the fabric the higher the sound absorption coefficient (α) at medium frequency level. The higher the number of layers or thickness of the fabric, the sound absorption through the fabric increases at medium frequency but after the maximum it remains almost unaltered. Three layer of cotton fabric gives maximum α approximately equal to 1 which is 1.104 mm thickness at frequency level of 3000-3500Hz and single knitted jersey gives maximum α at 4thlayer of 2200-2700Hz. Meanwhile , the α of biopolymer foam laminated with polyester fabric approximately equal to 1 at lower frequency level of 2000-3000Hz with lower thickness that is 0.668mm. Polyester fabric with lowest thickness shows better α at lower frequency level due to the structure of the fabric. The relationships among the fiber properties such as fiber density, fiber diameter, and fibrous material layer were considered as a factor that influences the sound absorption property.

scholarly journals Sound absorption property of nonwoven based composites

2013 ◽  
Vol 13 (4) ◽  
pp. 150-155 ◽  
Author(s):  
Eulalia Gliścińska ◽  
Marina Michalak ◽  
Izabella Krucińska
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Sound Absorption ◽  
Thermoplastic Composites ◽  
Absorption Property ◽  
Optimal Conditions ◽  
Composite Surface ◽  
Absorbing Materials ◽  
Thermal Pressing ◽  
Materials Used

Abstract Sound absorbing materials used to provide optimal conditions in rooms can be applied in the form of textiles with a special structure such as nonwovens or fibre-containing composites. Nonwovens can be successfully used to make thermoplastic composites by thermal pressing. This paper presents the comparison of the sound absorbing properties of needled nonwovens and composites made from them. Composites with various densities can be made of nonwovens with various percentage contents of filling and matrix fibres. The sound absorption by composites with similar thickness, about several millimetres, is slightly lower than that by the laminar nonwoven packs used for their making. The optimal content of the filling fibres in the composite, when its sound absorption coefficient reaches the highest values, is at the level of 10 wt.%. With the increase in the content of filling fibres the composite density decreases. In the case of the composite with 10 wt.% of filling fibres, its density is the highest among the composites investigated, and the increase in absorption of high-frequency sounds is the highest. Imparting a relief with a protrusion diameter over 10 mm to the composite surface, we can increase the sound absorption of that composite.

UTILIZATION OF OIL PALM TRUNK (ELAEIS GUINEENSIS) AS FOAM COMPOSITE FOR SOUND ABSORPTION

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Shafizah Sa’adon ◽  
Anika Zafiah M. Rus
Keyword(s):  
Absorption Coefficient ◽  
Oil Palm ◽  
Sound Absorption ◽  
Elaeis Guineensis ◽  
Filler Loading ◽  
Sound Absorption Coefficient ◽  
Polymer Foam ◽  
Oil Palm Trunk ◽  
Frequency Level ◽  
Foam Composite

Oil Palm Trunk (OPT) act as a filler for polymer foam composite has been investigated and proved to have ability to absorb sound. In this study, treatment of wood untreated and treated with acid hydrolysis named as UP5 and TP5 was use as filler. This study was developed to compare the ability of sound absorption based on different composition of filler in polymer foam composite. By choosing the size of <500 µm, three different percentage has been selected which is 10 %, 15 % and 20 % for both conditions. These samples has been tested by using Impedance Tube test according to ASTM E-1050 for sound absorption coefficient, α measurement and Scanning Electron Microscopy (SEM) for determine the porosity for each  samples. 20 % filler loading of UP5 gives highest sound absorption coefficient of 0.97 at 4728 Hz. Meanwhile for 20 % loaded of TP5 gives 0.99 at 3371 Hz. When comparing the sound absorption coefficient for both sounds absorbing materials, TP5 polymer foam composite showed higher value of sound absorption coefficient, α at lower frequency level (Hz) as compared to UP5 polymer foam composite which gives better results in sound absorption.

Effect of Coating Thickness on Sound Absorption Property of Four Wood Species Commonly Used for Piano Soundboards

2020 ◽  
Vol 52 (1) ◽  
pp. 28-43 ◽  
Author(s):  
Wei Xu ◽  
Xiaoyang Fang ◽  
Jiatong Han ◽  
Zhihui Wu ◽  
Jilei Zhang
Keyword(s):  
Coating Thickness ◽  
Wood Species ◽  
Sound Absorption ◽  
Absorption Property

A dynamic model for far-field acceleration

1982 ◽  
Vol 72 (4) ◽  
pp. 1049-1068
Author(s):  
John Boatwright
Keyword(s):  
Stress Drop ◽  
High Frequency ◽  
Dynamic Stress ◽  
The Body ◽  
Body Waves ◽  
Far Field ◽  
Rupture Velocity ◽  
Frequency Level ◽  
Average Change ◽  
Dynamic Stress Drop

abstract A model for the far-field acceleration radiated by an incoherent rupture is constructed by combining Madariaga's (1977) theory for the high-frequency radiation from crack models of faulting with a simple statistical source model. By extending Madariaga's results to acceleration pulses with finite durations, the peak acceleration of a pulse radiated by a single stop or start of a crack tip is shown to depend on the dynamic stress drop of the subevent, the total change in rupture velocity, and the ratio of the subevent radius to the acceleration pulse width. An incoherent rupture is approximated by a sample from a self-similar distribution of coherent subevents. Assuming the subevents fit together without overlapping, the high-frequency level of the acceleration spectra depends linearly on the rms dynamic stress drop, the average change in rupture velocity, and the square root of the overall rupture area. The high-frequency level is independent, to first order, of the rupture complexity. Following Hanks (1979), simple approximations are derived for the relation between the rms dynamic stress drop and the rms acceleration, averaged over the pulse duration. This relation necessarily depends on the shape of the body-wave spectra. The body waves radiated by 10 small earthquakes near Monticello Dam, South Carolina, are analyzed to test these results. The average change of rupture velocity of Δv = 0.8β associated with the radiation of the acceleration pulses is estimated by comparing the rms acceleration contained in the P waves to that in the S waves. The rms dynamic stress drops of the 10 events, estimated from the rms accelerations, range from 0.4 to 1.9 bars and are strongly correlated with estimates of the apparent stress.

Fabrication of Ultra Low-Density Binderless Sandwiching Materials by Rapid Steam Injection

2016 ◽  
Vol 852 ◽  
pp. 1482-1487
Author(s):  
Fan Cheng ◽  
Yu Hao Jiang ◽  
Jin Bo Chen ◽  
Peng Bo Lu ◽  
Ling Feng Su ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Sound Absorption ◽  
Building Materials ◽  
Bending Strength ◽  
Injection Pressure ◽  
Steam Injection ◽  
Low Density ◽  
Absorption Property ◽  
Injection Process ◽  
Injection Technology

Eco-friendly building materials with perfect thermal insulation & sound absorption property have become intriguing and eye-catching in recent years. In this work, the ultra low-density binderless sandwiching materials were firstly fabricated with ultra low-density of 60-80 kg/m3 by self-designed rapid steam injection technology. The main experimental factor of density, holding time, transmission time, steam injection pressure and fiber’s dimension was respectively investigated to their effects on formation of the new building materials. IR, Py GC-MS and AFM analysis were performed to study the mechanism of binderless sandwiching materials under steam injection process. The bending strength, thermal insulation & sound absorption property of the new materials were also studied. This new building material with no resin use and no formaldehyde release is expected to be reserved as the sandwich for designing thermal insulation & noise reduction building materials.

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