• Title, Summary, Keyword: Perforated Panel System

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An Experimental Study to Develop the Perforated Panel System for Noise Chamber (소음쳄버용 다공판 시스템 개발을 위한 실험적 연구)

  • Lee, Young-Sup;Lee, Dong-Hoon;Chung, Kwang-Seop
    • Journal of the Korean Society for Railway
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    • v.12 no.5
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    • pp.806-810
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    • 2009
  • The air conditioner system that is used in large structure, such as hospital, hotel, railway platform and train generate a high level noise generally. A chamber with sound absorbing materials, such as glass wool and polyurethane foam, are installed in this system to reduce the noise. However, these chambers cause environmental problems owing to the sound absorbing materials recently. Therefore, we develop noise chamber a built-in perforated panel resonance system as eco-friendly chamber to solve this problems. This noise chambers show the same noise reduction performance as the current chambers in the range above 500Hz. But, it reduces the noise up to 8dB(A) comparison to the current chambers in the range 200Hz~400Hz.

An Experimental Study on the Effect of Air Space on the Absorption Property of Composite Absorption System (배후공기층이 복합흡음구조의 흡음특성에 미치는 영향에 관한 실험적 연구)

  • Oh, Yang-Ki
    • KIEAE Journal
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    • v.1 no.2
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    • pp.47-54
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    • 2001
  • Single sound absorbers such as porous materials, panels, and Helmholts resonators have limited performance with some extents of frequency region. For example, porous materials do not attenuate low frequency sounds, while panels do not absorb high frequency sounds. Composite absorption structure with coverings, porous materials, and air gaps are an alternative for wide band sound absorption. Slits, panels, perforated panels are those materials for coverings, glass wool, mineral wool, polyester, and polyurethane are frequently used porous materials. Air gap between the porous material and background surface is one of major factors which governs the absorption characteristics of composite absorption structures, especially in the low frequency area. Calculations and measurements show that the absorption coefficients of composite absorption structure, in mid and low frequency bands, are getting higher with increased air gaps. Perforated panels rather than slits and panels are good coverings with higher number as far as absorption coefficient is concerned. Perforated panels with porous materials and 37 cm of air gaps in background have high absorption coefficients for all frequency bands, above 0.7 to 1.0. All measurements are performed in reverberation chamber, Mokpo National University, according to ISO 354 and ISO 3382.

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User-Participated Design Method for Perforated Metal Facades using Virtual Reality (가상현실 기반 사용자 참여형 타공패널 파사드 설계 방법론)

  • Jang, Do-Jin;Kim, Seongjun;Kim, Sung-Ah
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.36 no.4
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    • pp.103-111
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    • 2020
  • Perforated metal sheets are used as panels of facades for controlling environmental factors while ensuring user's visibility. Despite their functional potentials, only a specific direction of facades or an orientation of a building was considered in the relevant studies. This study proposed a design methodology for the perforated panel facades that reflects the location on the facades and the user's requirements. The optimization of quantitative and qualitative performance is achieved through communication between designers and users in a VR system. In optimizing quantitative performances, designers use machine learning techniques such as clustering and genetic algorithm to allocate optimal panels on the facades. In optimizing qualitative performances, through the VR system, users intervene in evaluating performances whose preferences are depending on them. The experiment using the office project showed that designers were able to make decisions based on clustering using GMM to optimize multiple quantitative performances. The gap between the target and final performance could be narrowed by limiting the types of perforated panels considering mass customization. In assessing visibility as a qualitative performance, users were able to participate in the design process using the VR system.

A Research on the Noise Reduction of Range Hood for Household (가정용 레인지 후드의 소음저감에 관한 연구)

  • Hong, Byung-Kuk;Song, Hwa-Young;Lee, Dong-Hoon;Lee, Chang-Kun;Kim, Dong-Yun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.449-452
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    • 2005
  • This paper introduces a study for the noise reduction of a range hood for household. Generally, range hoods have a built-in sirocco fan from which squawky noises are generated. Though the squawky noises have low noise level, these kinds of noises make most of the users nervous. For the purpose of noise reduction, in this study, a perforated plate system is installed in the fan housing of range hood. From the experimental results, it is confirmed that the noise level omitted front the range hood is decreased above 2dB(A) in all frequency regions due to the effect of noise reduction by perforated panel system.

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Acoustic modeling of an air cleaner filter in the engine intake system (자동차 흡기계 공기 여과기 필터의 음향학적 모델)

  • Ih, Jeong-Guon;Kang, Jang-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.114-117
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    • 2006
  • The air filter in engine intake system has a function of filtrating the dirt in the scavenging air as well as attenuating the noise. The noise attenuation within the air cleaner filter, however, has been regarded as negligible by the field engineers. In this paper, for the analysis of the acoustical performance of air filter, an acoustical model was suggested and the characteristics of air filter system were investigated. Fibrous structure of the filter element was modeled as a micro-perforated panel using the flow resistivity and porosity. The pleated geometry of the filter element was modeled as two coupled ducts that have permeable walls, in which each duct area was assumed being constant. Using such simplified geometry, a mathematical model was developed for the sound propagation within a narrow duct system. Visco-thermal effect was considered in modeling the sound propagation through such tubes; the filter box was modeled as a rigid rectangular box. By combining two models, a four-pole transfer matrix was derived. For the validation purpose, transmission loss was measured for a plastic rectangular box containing an air filter. A noticeable effect of the air filter element was observed by including the filter into the box. Comparing the predicted and measured data, we found that the predicted TL agrees well with experimental results, in particular, in magnitude and frequency at TL troughs.

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Acoustical Characteristics of Air Filter in the Engine Intake System (엔진 흡기계 공기 여과기의 음향 특성)

  • Kang, J.H.;Ih, J.G
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.190-193
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    • 2005
  • The air filter in engine intake system filters the dirt in the breathing air but also it attenuates the noise although the phenomenon has been regarded negligible. For the analysis of the acoustical performance of air filter, an acoustical model is suggested in this paper. The air filter consists of a porous filter element, which catches the particulate dirt, and a plastic filter box, which supports the filter element. Fibrous structure of the filter element is modeled as a micro-perforated panel using the flow resistivity and porosity. The pleated geometry of the filter element is modeled as two coupled ducts and a mathematical model is developed for the analysis of sound propagation. The filter box Is modeled as a rigid rectangular box. By combining two models, a 4-pole transfer matrix for the air filter is derived. The transmission loss calculated using the transfer matrix of the suggested model is compared with the measured data. Reasonably good agreement is observed. The result can be improved by considering the visco-thermal effect in modeling, in particular at a frequency range near the troughs of TL curve.

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Development of the E/R Insulation Modeling Automation System Using Structural Hull Model Information (선체 구조 모델 정보를 활용한 E/R Insulation 모델링 자동화 시스템 구축)

  • Park, Hoe-Yeon;Kang, Hyun-Gu;Park, Nam-Soo;Lee, Man-Sub
    • Special Issue of the Society of Naval Architects of Korea
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    • pp.112-117
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    • 2008
  • The Insulation, which is consist of the glass wool, mineral wool or perforated SUS plate, installed on the wall or under ceiling for the protecting heat and the blocking the noise of engine room area. In our shipyard, designing the structure model of insulation is hard and difficult, Because designed the insulation model is considered of any factors which are hull model properties of panel shape, direction and thickness and service of area. In this paper, We issue the way to utilize shape and direction of the hull model information and specific character of working space in engine room.

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Effect of Temperature and Gas Permeability of Functional Packing Films on Storability of Fresh-cut Salicornia herbacea Classified by Size (저장온도와 기능성 필름의 기체 투과도가 다양한 크기의 퉁퉁마디 신선편이의 저장성에 미치는 영향)

  • Baek, Jun Pill;Lee, Han Jong;Choi, In-Lee;Jung, Hyun Jin;Son, Jin Sung;Kim, Il Seop;Jeong, Cheon Soon;Kang, Ho-Min
    • Protected Horticulture and Plant Factory
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    • v.22 no.2
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    • pp.175-181
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    • 2013
  • These studies were identified the effect of four types of non-perforated breathable (NPB) packing film and three sizes on storage ability of fresh-cut for ready to eat packaging at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days storage in Salicornia herbacea. The fresh weight loss was less than 2% in every films at $5^{\circ}C$ condition after 25 days storage, and the $10^{\circ}C$ also had same result on 15 days storage except 100,000 cc NPB film. Compare with storage after 15 days, storage condition at $5^{\circ}C$ had shown better result under the 1% fresh weight loss rate. The 5,000 cc and $5^{\circ}C$ condition had been shown the characteristics of MA packaging in carbon dioxide and oxygen concentrations. The ethylene concentration in vacuum film was higher 10 to 100 times than in NPB film treatments during storage. But ethylene concentration was not statistically significant differences among size treatments. Every conditions had been measured the anti-oxidant activity by DPPH method after storage at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days. S. herbacea at $5^{\circ}C$ had been more than twice of activity compare with that at $10^{\circ}C$. 100,000 cc NPB film had been higher contents of anti-oxidant activity at $5^{\circ}C$ and $10^{\circ}C$. As the fresh-cut sizes, 3 cm and 5 cm sizes had changed depending on film types but 10 cm were not effected by the film types in the DPPH activity. When panel test had been tried to measure the visual quality and off-flavor after storage, $5^{\circ}C$ with a filme of 5,000 cc treatment had established higher value than other treated conditions. As these results, it's may be suggested that the $5^{\circ}C$ with 5,000 cc non-perforated breathable film for MA storage in Salicornia herbacea at fresh cut distribution system. Fresh cut size 10 cm with 100,000 cc NPB film also had the good quality for 15 dyas storage at $10^{\circ}C$, and this result can be applied for short term distribution system in Korea.