Small-scale transmission loss facility for flat lightweight panels

2009 ◽  
Vol 57 (5) ◽  
pp. 536 ◽  
Author(s):  
Shankar Rajaram ◽  
Tongan Wang ◽  
Steven Nutt
Keyword(s):  
Transmission Loss ◽  
Small Scale ◽  
Lightweight Panels

scholarly journals Sound Attenuation Study of Micro-Scale Acoustic Package

2020 ◽  
Vol 25 (2) ◽  
pp. 133-140
Author(s):  
Fuxi Chang ◽  
George T. Flowers ◽  
Robert N. Dean ◽  
Jeffrey C. Suhling ◽  
Jordan C. Roberts
Keyword(s):  
Microelectromechanical Systems ◽  
Transmission Loss ◽  
Acoustic Noise ◽  
Small Scale ◽  
Rigid Boundary ◽  
Expansion Chamber ◽  
Acoustic Effect ◽  
Micro Scale ◽  
Mems Gyroscopes ◽  
The Impact

Certain microelectromechanical systems (MEMS), particularly MEMS gyroscopes, are notably susceptible to high power acoustic noise, especially when the noise is at or near its resonant frequency. A micro scale open-through dual expansion chamber (ODEC) array package with a continuous transmission loss (TL) in a wide frequency range is proposed to diminish the impact of such noise on the performance of MEMS gyroscopes. An analytical model based on planar wave propagation in stationary air has been developed with the consideration of the thermo-acoustic effect near the inner rigid boundary regarding small scale. Experiments with ODEC groups and control groups (non-ODEC) samples have been conducted to verify the model and compare the performances. The ODECs perform in the manner of low-pass filters and both the experimental and the analytical results exhibit greater TL in the higher frequency ranges as compared to the corresponding control samples. In addition, the resonance effects of the ODEC itself are also experimentally observed to be a key factor in influencing the TL.

Analysis of Noise Level and Sound Transmission Loss (STL) of Noise Barrier Material for the Construction Site

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
W. H. Tan ◽  
◽  
S. Amares ◽  
W. Faridah ◽  
W. K. Heng ◽  
...  
Keyword(s):  
Sound Source ◽  
Noise Level ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Small Scale ◽  
Sound Transmission Loss ◽  
Aluminium Foil ◽  
Barrier Material ◽  
Barrier Materials ◽  
Noise Barrier

The construction activities are commonly known as the noisy and annoying work that affects a human’s routine. Those students and lecturers whose location are at the noise receptor locations might be suffering from the health impairment. The objective of this study is to assess and determine the noise level present throughout the daytime period (9AM - 12PM and 2PM - 5PM) at respective measurement points. The analysis of noise spectrum of the sound source from 125 Hz to 4 kHz is part of the scope of study as well. The analysis was carried out by comparing the recommended safe noise level with the equivalent continuous sound level (LAeq) and sound pressure level (Lp) gathered from this study. By setting up a barrier to shield or enclose the sound source is the common way to control the noise transmission. Therefore, selection of the best noise barrier materials is based on the sound transmission loss (STL) value. In this study, the experiment STL of four different types of noise barrier material (newspaper, aluminium foil, cotton and EPS foam) also was carried out in the small scale of reverberation chambers equipped with the LMS Test Lab and LMS SCADAS Mobile device. The 16 tested one-third octave frequency band ranging from 125 Hz to 4 kHz had been utilized in this study. The results revealed that the material of newspaper produced the STL ranging from 0 dB to 9.7 dB within the low frequency of 125 Hz to 800 Hz. Meanwhile, the aluminium foil, had the optimum performance with at least 5.4 dB and above for the STL value at higher frequency ranging from 1 kHz to 4 kHz. Generally, the newspaper is considered as the best noise barrier material as it able to reduce the noise level more throughout the selected frequency range in this study.

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

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