Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 34 for “"Sound absorption"”.
-
Sound absorption performance of EFBMF panel for building acoustic material
… flow resistivity. This will results in higher sound energy to be converted to heat and resulting in higher absorption. Absorption performance of EFBMF panel achieved 0.58 coefficients with optimum thickness, bulk density and apparent porosity value of 4.5 cm, 0.375 g/cm3 and 65.5 % …
-
Development of polymer based nanocomposite using electrospinning for sound absorption and isolation
… noise. In order to obtain promising results for sound absorption, these materials should have a large volume. Nanofibers, derived from polymeric materials, offer enormous benefits, and therefore, there is an intense focus on how this technology can be implemented to improve the performance of …
-
Confirming sound absorption characteristics of box absorbers that utilize laser-cut micro-slits on the top surface as the means of sound absorption, with an exploration of different architectural installations
… in micro-slits on their surfaces to absorb sound [8]. These box absorbers were developed through research at SINTEF and the Norwegian University of Science and Technology, and current research has tested this sound absorbing technology in standing wave tubes and in a controlled reverberation …
-
Sound Absorption and Sound Power Measurements in Reverberation Chambers Using Energy Density Methods
… spatially averaged squared pressure to calculate sound absorption, sound power, and other sound measurements. While a reverberation chamber provides an approximation of a diffuse sound field, variations in the measurements introduce uncertainty in measurement results. Room qualification procedures …
-
Sound absorption characteristic of lightweight brick containing Expanded Polystyrene Beads (EPS) and Palm Oil Fuel Ash (POFA)
… objectives of this research is to identify the sound absorption characteristic of lightweight bricks containing expanded polystyrene beads (EPS) and palm oil fuel ash (POFA). In order to fulfill the standard of a lightweight brick to be used as a building element, the physical and mechanical …
-
Acoustic metamaterials comprised of dead-end pores and black hole effect for low frequency sound absorption in linear and nonlinear regimes
… particularly for mitigation of low frequency sound of high intensity. The absorbers designed are formed of a series of plates with a central perforation, separated by air cavities. Two types of structures are investigated: the first has a central perforation with a constant radius (pancake …
-
Application of cepstral signal processing techniques and a guard tube to the in-situ measurement of the normal incidence sound absorption coefficient
… the in situ measurement of the normal incidence sound power absorption coefficient of homogenous materials. The work stemmed from an International Standards Organisation (ISO) working group, ISO/TC 43/SCJ WG38, tasked to formulate a new international standard: " Procedure for measuring sound …
-
Acoustical characteristic of empty fruit bunch (EFB) fibre with influence of sodium hydroxide treatment time and decay lifespan
… which is the ability to maintain the quality of absorption due to the lack of information and research on the acoustic application. Thus, in this research, the untreated and treated Empty Fruit Bunch (EFB) fibre was investigated as control unit and the standard used for sound absorption test was …
-
The effect of Meranti Merah wood fiber loading and sizes to the absorption property of polymer foam composites
… Polymer foam composites (PFC) were developed for absorption material based on epoxy, renewable monomer from waste cooking oil, isocyanates and wood fiber fillers. The polymer foam composite (PFC) were fabricate based on four percentages of wood fiber filler loading which are 5, 10, 15, and 20 wt% …
-
The evaluation of acoustic characteristic performance on natural sound absorbing materials from cogon grass waste
… fibers are been used widely in the field of sound absorption due to their superior characteristics such as durable and chemical resistant. However, there are several disadvantages of synthetic fibers such as non-biodegradability and hazards to the health of human. In this research, the …
-
The evaluation of acoustic characteristic performance on natural sound absorbing materials from cogon grass waste
… fibers are been used widely in the field of sound absorption due to their superior characteristics such as durable and chemical resistant. However, there are several disadvantages of synthetic fibers such as non-biodegradability and hazards to the health of human. In this research, the …
-
The evaluation of acoustic characteristic performance on natural sound absorbing materials from cogon grass waste
… fibers are been used widely in the field of sound absorption due to their superior characteristics such as durable and chemical resistant. However, there are several disadvantages of synthetic fibers such as non-biodegradability and hazards to the health of human. In this research, the …
-
Acoustical characteristics of oil palm mesocarp fibres
… Incorporated polyurethane (PU) had improved the sound absorption coefficient (SAC), especially at low frequency range. The oil palm Mesocarp fibres were mixed with four different percentages of PU, namely 10%, 20%, 30% and 40%. The measurement of SAC was done using an impedance tube method (ITM). …
-
Physical and acoustic properties of petroleum and renewable based polyurethane foam filled with shorea leprosula
… ability of polymer foam composites (PF) towards sound absorption coefficient (SAC) based on the wood fiber size with range of 150-200 μm (powder), 250-300 μm (fibrous) and 900-1000 μm (flakes). 5 wt%, 10 wt%, 15 wt% and 20 wt% of SL filler content and thickness of 10 mm, 20 mm and 30 mm were used …
-
Fabrication and Evaluation of Specialty Nonwoven Materials
… materials with high performance on chemical absorption, adsorption and on acoustic absorption and insulation using natural fiber nonwovens via carbonization and activation. Evaluation of these textile materials includes tensile strength, thermogravimetric analysis, sound absorption and …
-
Study on single and double layers micro-perforated panel absorbers and optimal design by genetic algorithm
… of micro-perforated panel absorber, the acoustic absorption performance of single and double layers MPP absorbers are investigated. The analytical formula for calculating the absorption coefficient of single and double layers micro-perforated panel are derived by the equivalent circuit method. …
-
Exploring Novel, Hard, Acoustically Absorbent, Materials
… wall or ceiling material treatment that is more sound absorbent than other common surface treatments. To find a material answer to this desire an impedance tube was used to analyze the mid-frequency octave band absorption coefficients of various re-purposed existing materials and tiles created …
Page 1 of 2