Search or ask a question

Does the sound absorbtion increase when the air flow resistivity increase porous materials?

Sound transmission class

Noise reduction coefficient

Best insight from top research papers

Increasing the air flow resistivity of porous materials can indeed enhance sound absorption. Research has shown that the addition of an air gap with a multilayer of porous material can improve low to medium-frequency sound absorption significantly . Moreover, incorporating rigid scatterers periodically within porous materials can boost their transmission loss, especially with the Bragg diffraction effect, indicating an increase in sound absorption capabilities . Additionally, the use of natural porous materials like jute and waste cotton has been explored for their sound absorption properties, with mathematical models predicting absorption coefficients based on airflow resistivity and complex wave numbers . Overall, manipulating the air flow resistivity in porous materials can lead to improved sound absorption performance across different frequencies.

Answers from top 5 papers

PDF

Open Access

More filters

Papers (5)	Insight
Book Chapter•DOI Experimental Investigation of Sound Absorbing Materials 01 Jan 2023	The absorption coefficient of porous materials increases with higher air flow resistivity, impacting sound absorption capabilities, as investigated in the study on sound absorbing materials.
Open access•Journal Article•DOI Sound transmission loss of porous materials in ducts with embedded periodic scatterers D.P. Jena, Xiaojun Qiu - Show less +1 more 10 Feb 2020-Journal of the Acoustical Society of America 7 Citations	Yes, sound absorption increases in porous materials with higher air flow resistivity when periodic scatterers are embedded due to Bragg diffraction, as shown in the study.
Journal Article•DOI Sound Absorption of the Absorber Composed of a Shunt Loudspeaker and Porous Materials in Tandem Xin Li, Bilong Liu - Show less +1 more 15 Jul 2023-Polymers	Increasing air flow resistivity of porous materials can enhance sound absorption when combined with a shunt loudspeaker, as shown in the study, achieving broadband absorption across multiple octaves.
Book Chapter•DOI Prediction of Acoustical Performance with and Without Airflow Resistivity of Fibrous Natural Materials Manish Raj, Shahab Fatima, Naresh Tandon - Show less +2 more 01 Jan 2021	Increasing airflow resistivity in porous materials can enhance sound absorption by increasing dissipation and transmission of sound waves, as discussed in the research paper.
Journal Article•DOI Enhancement of low and medium frequency sound absorption using fabrics and air gaps Bethalihem Teferi Samuel, Marcin Barburski, Ewa Witczak, Adam K. Puszkarz - Show less +3 more 12 Jul 2023-Textile Research Journal	Increasing air flow resistivity in porous materials can enhance sound absorption, especially when combined with fabric layouts and air gaps, as observed in low to medium frequencies in the study.

My columns

Related Questions

How does the use of porous media affect heat transfer in various industrial processes?5 answersThe use of porous media significantly impacts heat transfer in various industrial processes. Porous materials, with their unique properties like porosity, pore size, and distribution, enhance heat transfer rates by increasing surface area for improved thermal efficiency. Studies on double-pipe heat exchangers reveal that different types of porous media, such as ceramic balls, steel balls, and glass balls, can enhance thermal conductivity and heat transfer efficiency in heat exchangers. Additionally, investigations into porous media heat transfer with laminar pulsating airflow show that symmetrical pulsations intensify heat transfer, leading to empirical correlations for predicting heat transfer in such systems. Furthermore, numerical studies on Rayleigh–Benard convection through random porous media demonstrate that decreasing porosity can enhance heat transfer by improving the cross-correlation between fluid velocity and temperature fluctuations.

What is the connection between air flow resistivity and sound absorbtion?4 answersAir flow resistivity plays a crucial role in determining the sound absorption capabilities of porous materials. The measurement of air flow resistivity is standardized by ISO 9053, which offers methods like steady-state and alternating air flow techniques. Higher air flow resistivity leads to increased sound absorption due to the dissipation and transmission of sound within the material. Researchers have explored natural materials like jute, waste cotton, bamboo, and others for their sound absorption properties, with air flow resistivity being a key parameter in predicting their sound absorption coefficients. The relationship between air flow resistivity and sound absorption is fundamental in acoustical studies, guiding the development of materials with enhanced noise control properties while considering environmental and health factors.

Does the decreasing resistivity of air increase the sound absorption properties of woven fabrics?5 answersThe decreasing resistivity of air does not directly increase the sound absorption properties of woven fabrics. Instead, the sound absorption properties of woven fabrics are influenced by various factors such as fabric structure, porosity, thickness, and yarn arrangement. Studies on woven fabrics have shown that factors like thickness, airflow resistivity, and yarn arrangement play crucial roles in enhancing sound absorption coefficients. Additionally, the porosity and roughness of the fabric structure also impact the effectiveness of noise reduction by woven fabrics. Furthermore, the microstructure of woven fabrics, including parameters like fiber diameter and porosity, significantly affects the fabric's capability to absorb sound. Therefore, while air gap and resistivity are important, they are part of a complex interplay of factors that determine the sound absorption properties of woven fabrics.

What is the connection between high vibration damping capacity and sound absorption?5 answersHigh vibration damping capacity is closely linked to sound absorption capabilities. Research on vibration testingand polymer compositesdemonstrates that materials with high damping capacity exhibit effective sound absorption properties. For instance, the evaluation of interpenetrating polymer networks showed that incorporating polymers like polyurethane and polymethyl methacrylate enhanced acoustic damping characteristics, leading to improved sound attenuation. Additionally, studies on bio-polymers derived from waste cooking oil revealed that materials with higher damping ratios transmitted vibrations effectively, contributing to better sound absorption. Furthermore, innovative damping vibration absorption assemblies have been designed to absorb high currents and attenuate vibrations, resulting in noise reduction and improved sound quality. Overall, materials with high vibration damping capacity tend to excel in sound absorption, making them valuable for noise control applications.

Are bamboo fibres better sound absorbers than wood fibres?5 answersBamboo fibres have been found to have sound absorption properties and show potential as sound-absorbing materials. The depth of bamboo twigs has been shown to affect the sound absorption coefficient, with greater depth resulting in higher absorption coefficients. Glued laminated bamboo (glubam) has been compared to spruce-pine-fir (SPF) and found to have similar or even better acoustic insulation performance. Additionally, a study on bamboo particle board coated with polyurethane (PU) found that the coating treatment improved surface characteristics and thickness, swelling, and water absorption, but also reduced acoustical properties at high frequencies. While these studies suggest that bamboo fibres have sound absorption capabilities, it is important to note that the comparison to wood fibres is limited and further research is needed to directly compare the two materials.

How do the porosity, pore size and pore size distribution of fibrous sound absorber affect the sound absorption performance?3 answersThe porosity, pore size, and pore size distribution of fibrous sound absorbers have a significant impact on their sound absorption performance. Porous absorbers allow sound to propagate through an interconnected pore network, resulting in sound energy dissipation. The optimization of these parameters can lead to improved sound absorption coefficients (SAC) in different frequency ranges and thicknesses. Metal foams, for example, are known for their strength, low mass, high hardness, and damping properties, making them effective sound absorbers. Additionally, the use of additive manufacturing technology, such as 3D-printing, allows for the design of macro-perforated porous media with specific pore sizes and porosities, enhancing their sound absorption performance. Overall, understanding and optimizing the porosity, pore size, and pore size distribution of fibrous sound absorbers can contribute to the development of more efficient acoustic absorption materials for various applications.

See what other people are reading

What existing methods or products are currently available to address the issue of keeping babies safe during sleep?

Existing methods and products to address the safety of babies during sleep include the development of industry codes, such as the one created by the ACCC's Product Safety Operations Group. Additionally, safe sleep bundles have been implemented in NICUs, incorporating policies, standardized sleep sacks, crib cards, and provider order sets in electronic health records to improve caregiver compliance. Novel testing methods have been explored to assess the safety of infant sleeping products, focusing on airflow and firmness tests to differentiate between safe and unsafe products. Furthermore, innovative systems like the PneuMat, integrating sensors and pneumatic drives, aim to ensure infants remain in safe sleeping positions through shape-changing capabilities. Recommendations by the American Academy of Pediatrics emphasize safe sleep practices, including supine positioning, firm sleep surfaces, and avoidance of soft bedding to reduce the risk of sleep-related infant deaths.How does an oven cook food?

An oven cooks food through various heat transfer methods such as convection, conduction, and radiation. It typically consists of electric or gas-powered heaters strategically placed within the oven chamber to provide the necessary heat for cooking. Some ovens may also incorporate features like water receptacles to create steam for moist cooking environments. Additionally, innovative designs may include filtration systems to improve air quality during the cooking process, enhancing user experience and health. Ovens can have multiple cooking chambers with separate heating elements that can be controlled individually, allowing for precise temperature adjustments and efficient cooking. By combining these heating mechanisms and control features, ovens can quickly and effectively cook food while maintaining high quality and energy efficiency.Distribution methods for nike?

Nike utilizes various distribution methods to enhance delivery precision. One method involves sorting and transferring shoes by grade through a shoe distributing and transferring unit, connected to a shoe distributing assembly for efficient distribution. Additionally, Nike focuses on improving delivery precision by quantifying areas in the supply chain for enhancement, particularly in upstream processes like PO creation. This approach allows Nike to prioritize efforts on areas needing improvement, ultimately enhancing delivery precision across the company. By implementing effective distribution strategies and continuously evaluating the supply chain, Nike can optimize its operations and ensure timely and complete product delivery to customers.How does the XRD rocking curve technique affect the determination of strong directionality in materials?

The XRD rocking curve technique plays a crucial role in determining the strong directionality in materials by analyzing diffraction patterns. This technique involves measuring crystal diffraction energy spectrums, correcting scattering factors, and extracting diffraction strength within specific angles. It considers the two-dimensional curvature of incident wave fronts, studying rocking curves' shape, position, and dimensions based on diffraction geometry asymmetry. Additionally, it records rocking curves using X-ray optical bending elements to study defect structure changes under external impacts. The technique also analyzes transmission coefficients, reflection coefficients, and rocking curves for asymmetrical Laue cases, revealing new peculiarities in thick crystals. Furthermore, the resolution function analysis in double-crystal schemes aids in precisely determining structural parameters by considering incident radiation distribution.What is diffusion cell?

A diffusion cell is a crucial tool used in various fields for studying mass transfer phenomena. It consists of chambers separated by a membrane, allowing the diffusion of substances from one compartment to another. Diffusion cells are employed in pharmaceutical research to evaluate drug permeability and release from formulations like creams and gels. They play a significant role in assessing the penetration capacity of compounds through the skin, aiding in the development of transdermal drug delivery systems. Additionally, diffusion cells are utilized in experiments involving the penetration of drugs through biological barriers like the cornea, providing a close-to-physiological environment for testing. Overall, diffusion cells are versatile devices essential for studying diffusion processes in various scientific and medical applications.What is a grain dryer machine?

A grain dryer machine is a device used for efficiently drying grains to reduce moisture content and prevent spoilage. Various types of grain dryer machines exist with different designs and functionalities. They typically consist of components such as drying chambers, agitators, heating mechanisms, and air circulation systems. These machines employ methods like hot-air suspension drying, steam heating, and controlled exposure to electromagnetic radiation to dry grains effectively. Some grain dryers utilize stirring plates, driving plates, and conveying devices to facilitate the drying process and improve efficiency. Overall, grain dryer machines play a crucial role in agricultural processes by ensuring grains are properly dried for storage and further use.How does low level of concentration affect cognitive function and productivity in individuals?

A low level of concentration can significantly impact cognitive function and productivity in individuals. Research has shown that concentration plays a crucial role in achieving maximum and faster results in work. When individuals are not concentrating, their memory test scores tend to be lower, leading to a decrease in correct answer rates and overall cognitive performance. Additionally, studies have indicated that maintaining a high level of concentration is essential for intellectual productivity, as distractions or lack of focus can hinder task performance. Therefore, it is vital to understand the influence of factors like indoor air quality and environmental conditions on concentration levels to optimize cognitive function and productivity in individuals.How does hand wash work?

Hand washing systems vary in design and functionality. Some systems, like those with a reagent and water dispensing unit, use sensors to monitor handwashing actions and send data to a server for analysis. Others, such as a hand-washing device with a water pumping mechanism and toy for children, make hand washing engaging and educational, promoting early habit formation. Additionally, a hand washing device with air supercharging capabilities uses water and air to effectively clean and dry hands, conserving water while ensuring thorough cleaning. Furthermore, a hand cleaning system with brushes positioned around a soap dispenser allows for manual scrubbing during hand washing. Lastly, a hand wash/dry machine integrates washing, drying, and sensor technologies to provide a comprehensive hand hygiene solution.How to calculate space cooling loads in German standard? Write as much detail as possible?

In the German standard for calculating space cooling loads, various methods can be employed, such as a monthly quasi-steady state method, a simplified hourly method, and detailed simulation. To enhance the accuracy of cooling load predictions, preprocessing of training data is crucial, including the removal of missing values during HVAC system off-times and adjusting structural parameters for model optimization. Understanding the impact of factors like indoor set point, heat sources, and convective heat transfer through the building envelope is essential for tailored cooling load calculations. Linear regression models based on radiant time series components have been developed to estimate cooling loads, considering factors like building materials, environment, and occupant characteristics. Additionally, interactive online programs have been designed to aid engineering and architecture students in learning residential cooling load calculations.What are the most effective types of water spraying systems for dust mitigation in construction site?

The most effective types of water spraying systems for dust mitigation in construction sites include nebulizer-retrofitted UAVs for aerial water spraying, water-sprinkling on roads, and optimized spray schemes for dust suppression at excavation faces. Studies show that water-sprinkling can efficiently remove PM particles from road surfaces and reduce their concentration in the environment, with different efficiencies based on road types. Additionally, the use of specific spray schemes with different pressure levels can significantly reduce dust concentrations at excavation faces, especially for larger dust particles. Moreover, magnetized water under specific conditions has been found to enhance dust removal performance and temperature reduction in underground environments, providing a theoretical basis for effective dust control measures in mines.What are the most effective mix methods for improving thermal comfort in interior spaces based on material selection?

To enhance thermal comfort in interior spaces through material selection, several effective methods can be employed. Integrating cool materials into urban environments can reduce air and surface temperatures, promoting airflow and mitigating heat stress. Earth-based materials, like soil floors, offer significant thermal comfort benefits compared to common floorings, showcasing the importance of material choice in indoor comfort. Innovative composite materials, such as 'SLNT-PCM', combining phase change materials with textiles, demonstrate improved thermal performance by stabilizing internal temperatures and reducing energy consumption in buildings. Additionally, utilizing earth-based construction materials like CSEB walls can significantly reduce warm thermal discomfort hours and cooling energy loads, contributing to sustainable dwellings in hot climates. Incorporating adaptive external walls with Phase Change Materials can dynamically respond to climate conditions, enhancing energy efficiency and achieving better thermal comfort in buildings.