A sound reduction semantics for untyped CBN mutli-stage computation. Or, the theory of MetaML is non-trival (extended abstract)

1999 ◽  
Author(s):  
Walid Taha
Keyword(s):  
Sound Reduction

Analysis of Sound Reduction and Strong Drag Composite Concrete Fibers Gedebok Banana Results Delignification with Sodium Hydroxide Solvent (Naoh)

2018 ◽  
Vol 6 (02) ◽  
pp. 105-120
Author(s):  
Muhammad Rouf Suprayogi ◽  
Annisa Mufida ◽  
Edwin Azwar
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Lignin Content ◽  
Sound Intensity ◽  
Cellulose Fiber ◽  
Cellulose Content ◽  
Cellulose Powder ◽  
Drying Method ◽  
Normal Concrete ◽  
Sound Reduction

In composite science, desirable materials that are lighter but have the power and quality that can match or even exceed the material that has been there before. The purpose of this study was to investigate the effect of cellulose fiber addition from banana gedebok to tensile strength, compressive strength and damping of concrete composite sound. To achieve this objective, mixing of cellulose fibers with K-275 quality concrete mix with variation of 0% and 5% substitution in which the cellulose is varied in powder and wicker form. Delignification of lignin content from banana gedebok was done by soaking and drying method without any variation and yielding powder having cellulose content of 13,0388%, hemicellulose 18,2796% and lignin 0,6684%. This study produces concrete composites that have a tensile strength and a compressive strength lower than that of normal concrete. Normally reinforced concrete tensile strength value 94.5 kg / cm2, 71.4 kg / cm2 cellulose powder concrete and 90.3 kg / cm2 cellulose woven concrete. Normal concrete compressive strength value 334,22 kg / cm2, cellulose powder concrete 215,7 kg / cm2, and cellulose webbing concrete 157,98 kg / cm2. As for the power damping sound of cellulose webbing concrete has the highest damping power compared to other concrete with the absorbed sound intensity that is 52-68 dB

Prediction of sound reduction index of plenum window by the surface impedance approach

2021 ◽  
Vol 175 ◽  
pp. 107851
Author(s):  
Liangfen Du ◽  
Siu-Kit Lau ◽  
Siew Eang Lee
Keyword(s):  
Surface Impedance ◽  
Sound Reduction ◽  
Reduction Index

Assessment of a simplified experimental procedure to evaluate impact sound reduction of floor coverings

2014 ◽  
Vol 79 ◽  
pp. 92-103 ◽  
Author(s):  
Andreia Pereira ◽  
Luís Godinho ◽  
Diogo Mateus ◽  
Jaime Ramis ◽  
Fernando G. Branco
Keyword(s):  
Experimental Procedure ◽  
Floor Coverings ◽  
Sound Reduction

scholarly journals A Metawindow with Optimised Acoustic and Ventilation Performance

2021 ◽  
Vol 11 (7) ◽  
pp. 3168
Author(s):  
Gioia Fusaro ◽  
Xiang Yu ◽  
Zhenbo Lu ◽  
Fangsen Cui ◽  
Jian Kang
Keyword(s):  
Natural Ventilation ◽  
Noise Control ◽  
Fem Analysis ◽  
The Finite Element Method ◽  
Noise Mitigation ◽  
Acoustic Performance ◽  
Potential Applications ◽  
Ventilation Performance ◽  
Sound Reduction ◽  
Window Design

Crucial factors in window performance, such as natural ventilation and noise control, are generally conceived separately, forcing users to choose one over the other. To solve this dualism, this study aimed to develop an acoustic metamaterial (AMM) ergonomic window design to allow noise control without dependence on the natural ventilation duration and vice versa. First, the finite element method (FEM) was used to investigate the noise control performance of the acoustic metawindow (AMW) unit, followed by anechoic chamber testing, which also served as the validation of the FEM models. Furthermore, FEM analysis was used to optimise the acoustic performance and assess the ventilation potential. The numerical and experimental results exhibited an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz. A good agreement between the measured and numerical results was obtained, with a mean variation of 30%. Therefore, the AMW unit optimised acoustic performance, resulting in a higher noise reduction, especially from 50 to 500 Hz. Finally, most of the AMW unit configurations are suitable for natural ventilation, and a dynamic tuned ventilation capacity can be achieved for particular ranges by adjusting the window’s ventilation opening. The proposed designs have potential applications in building acoustics and engineering where natural ventilation and noise mitigation are required to meet regulations simultaneously.

Untersuchung der Regelwerke für den passiven Schallschutz unter Berücksichtigung aktueller Verkehrslärmspektren – Teil 1

2020 ◽  
Vol 15 (01) ◽  
pp. 17-21
Author(s):  
J. Weinzierl ◽  
W. Wieland
Keyword(s):  
Correction Term ◽  
Spectral Composition ◽  
Sound Insulation ◽  
Assessment Procedure ◽  
Noise Sources ◽  
Frequency Dependent ◽  
Protection Goal ◽  
Passive Noise ◽  
Sound Reduction ◽  
Spectrum Adaptation

In den Regelwerken zum passiven Schallschutz von Umfassungsbauteilen wird das erforderliche Schalldämm-Maß der Fassade als Einzahlwert entsprechend dem Bewertungsverfahren nach DIN EN ISO 717-1 [1] ermittelt. Um die spektrale Zusammensetzung verschiedener Lärmquellen und die frequenzabhängige Schalldämmung von Fassadenbauteilen zu berücksichtigen, werden in den einschlägigen Regelwerken Korrektursummanden bzw. Spektrum-Anpassungswerte verwendet. Im folgenden Beitrag wird der Einfluss verschiedener Außenlärmspektren und frequenz- abhängiger Schalldämm-Maße auf den Innenpegel diskutiert. Insbesondere werden die Unterschiede zwischen Holz- und Massivbauweise bezüglich des Schutzziels bzw. des Innenpegels betrachtet. Die Untersuchungen zeigen, dass keine generelle Differenzierung zwischen Leicht- und Massivbauweise erforderlich ist. Für hochschalldämmende Leichtbaukonstruktionen mit einem Ctr,50–5000 < –8 dB wird jedoch ein Korrekturterm für das erforderliche Fassaden-Schalldämm-Maß zur Sicherstellung des Schutzziels vorgeschlagen. &nbsp; &nbsp; Summary In the regulations for passive noise protection of surrounding components, the required sound reduction index of the facade is determined as a single value according to the assessment procedure according to DIN EN ISO 717-1 [1]. In order to take into account the spectral composition of different noise sources and the frequency-dependent sound insulation of facade components, correction summands or spectrum adaptation values are used in the relevant regulations. The following article discusses the influence of various outside noise spectra and frequency-dependent sound insulation measures on the inside level. In particular, the differences between wood and solid construction were considered with regard to the protection goal and the internal level. The investigations show that no general differentiation between lightweight and solid construction is necessary. For highly sound-insulating lightweight constructions with a Ctr, 50–5000 <-8 dB, however, a correction term for the required facade soundproofing dimension to ensure the protection goal is proposed. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;

Sound absorption based on Micro-perforated panels and Acoustic Black Hole principle

2021 ◽  
Vol 263 (6) ◽  
pp. 548-555
Author(s):  
Xiaoqi Zhang ◽  
Li Cheng
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Sound Absorption ◽  
Practical Application ◽  
Inner Radius ◽  
Simulation Results ◽  
Structural Configurations ◽  
Acoustic Black Holes ◽  
Sound Reduction ◽  
Bending Wave

Acoustic black holes (ABHs) have been so far investigated mainly for bending wave ma-nipulation in mechanical structures such as beams or plates. The investigations on ABHs for sound wave manipulation, referred to as Sonic black holes (SBHs) are scarce. Existing SBH structure for sound reduction in air is typically formed by putting a set of rings inside a duct wall with decreasing inner radius according to a power law. As such, the structure is very complex and difficult to be practically realized, which hampers the practical application of SBHs for sound reduction. This study explores the possibilities of achieving SBH effects using other types of structural configurations. In particular, micro-perforated panels are proposed to be introduced into the conventional SBH structure, and the simulation results show that the new formed SBH structure is simpler in configuration in terms of number of rings and more efficient in terms of sound energy trapping and dissipation.

A Study on Absorption Coefficient of Sustainable Acoustic Panels from Rice Husks and Sugarcane Baggase

2015 ◽  
Vol 1113 ◽  
pp. 198-203 ◽  
Author(s):  
Farrah Zuhaira Ismail ◽  
Mohamad Nidzam Rahmat ◽  
Norishahaini M. Ishak
Keyword(s):  
Absorption Coefficient ◽  
Rice Husk ◽  
Sound Absorption ◽  
Phenol Formaldehyde ◽  
Agricultural Waste ◽  
Rice Husks ◽  
Porosity Level ◽  
Agriculture Waste ◽  
Single Piece ◽  
Sound Reduction

Noise has detrimental effects on human lives and it is a nuisance to the environment. As many of the available sound reduction materials in the current market are hazardous, there are demands for alternative sustainable materials to reduce the noise problem. Therefore, the aim of this research is to study the potential of using an agricultural waste as sound absorption panel. For the purpose of this study, the combination of two materials was under studied; rice husks and sugarcane baggase. There were two main objective of the research; first is to develop absorption panels from the combination of rice husks and sugarcane baggase at different percentage of mixture. Second objective is to identify the absorption rate of the panels. The study encompasses the fabrication of the sustainable sound panels using the rice husk and sugarcane fibre and bond using Phenol formaldehyde (PF). Five panels of sized 12 inch x 12 inch and 12 mm thick were fabricated. The absorption coefficient of the samples was done at the acoustic lab, Faculty of Engineering & Build Environment, Universiti Kebangsaan Malaysia (UKM), Bangi. The panels were tested using an impedance tube. The procedure of the test was carried out in accordance with ISO 10534-2:1998 standards. Based on the results, sample 1 gave the highest absorption coefficient compared to sample 2, 3, 4 and 5. It can be concluded that the acoustic panel made from a mixture of 100% rice husks had higher absorption co-efficient compared to the performance of the other samples given the fact that the characteristic of the rice husks which has air gap in every single piece of rice husk. The spongy properties of the sample 1 panel has created many void spaces which encouraged more sound absorption capability due to the porous surface of the panel. Sound absorption is very much affected by the availability of porosity level of the panel. Thus, further studies on other potential materials from waste should be conducted.Keywords. Noise, Agriculture waste, sound, absorption panels, absorption co-efficient

Additional noise reduction with diffracting elements on barriers: experimental testing

2021 ◽  
Vol 263 (4) ◽  
pp. 2654-2664
Author(s):  
Wout Schwanen ◽  
Mark Mertens ◽  
Ysbrand Wijnant ◽  
Willem Jan van Vliet
Keyword(s):  
Noise Reduction ◽  
Experimental Testing ◽  
Low Noise ◽  
Motor Vehicles ◽  
Additional Element ◽  
High Noise ◽  
Quarter Wavelength ◽  
Noise Barrier ◽  
Sound Reduction ◽  
Development And Validation

The noise reduction of a (low) noise barrier can be enhanced by using an additional element with quarter-wavelength resonators with varying depths. The so-called WHISwall or WHIStop deflects sound upwards for specific frequencies creating an additional sound reduction. Different experiments on the WHISwall and WHIStop are performed as input for model validation. The development and validation of the model are described in a separate paper. In this paper the measurement campaign and its results are presented. We performed measurements on two setups. The first setup consists of a 1.1 meter high WHISwall, a 1.1m high noise barrier and a reference section (without noise measure). Measurements have been conducted with both an artificial sound source and pass by measurements with light and heavy motor vehicles. In a second test setup, the WHIStop was placed on top of a 4 meter high noise barrier and the diffraction was determined according the European standard EN 1793-4.

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