The Analysis of the Octave-Band Self-Complementary Antenna

2021 ◽  
Author(s):  
Hitoshi Yoshimura ◽  
Kazufusa Noda ◽  
Keiichi Hirano ◽  
Yasuhiro Tsunemitsu
Keyword(s):  
Octave Band

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

scholarly journals Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

Effect of ceiling and dry-type double floor on heavy-weight floor impact sound in concrete building and CLT building.

2021 ◽  
Vol 263 (3) ◽  
pp. 3064-3072
Author(s):  
Takashi Yamauchi ◽  
Atsuo Hiramitsu ◽  
Susumu Hirakawa
Keyword(s):  
Frequency Band ◽  
Sound Level ◽  
Center Frequency ◽  
Sound Insulation ◽  
Octave Band ◽  
Band Center ◽  
Heavy Weight ◽  
Concrete Building ◽  
Floor Structure ◽  
Insulation Performance

The air layer between the interior finishes and the structure is used as piping and wiring space. In many cases, ceilings and dry-type double floors are commonly constructed in Japan. However, the effect of the air layer of ceilings and dry-type double floors on the heavy-weight floor impact sound insulation performance has not yet quantitatively investigated. Therefore, in this study, the same floor and ceiling structures were constructed for concrete and CLT buildings, and the heavy-weight floor impact sound was investigated. As results, it was confirmed that the reduction amount of the heavy-weight floor impact sound by the ceiling tended to be smaller in CLT buildings than in concrete buildings. However, the trends were similar. Due to the dry-type double floor structure, the heavy-weight floor impact sound level was increased in concrete building and decreased in CLT building at 63 Hz in the octave band center frequency band. Therefore, it can be said that the dry-type double floor structure can be used to improve the heavy-weight floor impact sound performance in the CLT building.

Magnitude Estimation of Loudness I Application to Hearing Aid Selection

1984 ◽  
Vol 27 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Daniel Geller ◽  
Robert H. Margolis
Keyword(s):  
Magnitude Estimation ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Hearing Impaired ◽  
Octave Band ◽  
Loudness Function ◽  
Comfortable Loudness ◽  
Tonal Stimuli

Three experiments were conducted to explore the utility of magnitude estimation of loudness for hearing aid selection. In Experiment 1 the loudness discomfort level (LDL), most comfortable loudness (MCL), and magnitude estimations (MEs) of loudness were obtained from normal-hearing subjects. MCLs fell within a range of loudnesses that was relatively low on the loudness function. The LDLs were lower than previously published values. Experiment 2 was performed to identify the source of disparity between our LDL data and previously reported results. The effects of instructions are demonstrated and discussed. In Experiment 3 magnitude estimations of loudness were used to determine the loudness of tonal stimuli selected to represent ⅓ octave band levels of speech. Over the 500–4000 Hz range, the contributions of the various frequency regions to the loudness of speech appears to be nearly constant. Methods are proposed for (a) predicting the frequency-gain response of a hearing aid that restores normal loudness for speech for the hearing-impaired listener and (b) psychophysically evaluating the compression characteristic of a hearing aid.

scholarly journals Quadrature signal splitting technique offering octave-band performance

2001 ◽  
Vol 37 (4) ◽  
pp. 262 ◽  
Author(s):  
P.A. Warr ◽  
M.A. Beach ◽  
J.R. MacLeod ◽  
J.P. McGeehan
Keyword(s):  
Octave Band ◽  
Splitting Technique ◽  
Quadrature Signal

scholarly journals Octave Band Technique for Noise Measurement at the Source, Path, and Receiver of Gas Turbines in Oil and Gas Facilities

2022 ◽  
Vol 30 (1) ◽  
pp. 725-745
Author(s):  
Akmal Haziq Mohd Yunos ◽  
Nor Azali Azmir
Keyword(s):  
Gas Turbine ◽  
Noise Level ◽  
Gas Turbines ◽  
Noise Exposure ◽  
Oil And Gas ◽  
Noise Pollution ◽  
Noise Measurement ◽  
Octave Band ◽  
High Noise ◽  
Safety And Health

Noise measurement is essential for industrial usage. However, further attention to preventing noise pollution is needed, especially when working with equipment generating a high noise level, such as gas turbines. This study aims to determine the best way to perform noise measurement and analyze the octave band frequency generated by noise pollution caused by gas turbine equipment. Data from site measurements show that the gas turbines produce more than 85 dB of noise with a Z-weighted measurement. A noise measuring investigation was conducted to obtain the data for the 1/3 octave band. A frequency-domain was used to comprehend the properties of the noise measurement frequency band. The frequency band was classified into three different zones called low, medium, and high frequency, which is useful in noise measurement analysis to identify a viable solution to reduce the noise. On-site sampling was performed at the source, path, and receiver of three separate gas turbine locations within oil and gas operations. The 1/3 octave band data collection results at the sound source, path, and receiver demonstrate the noise level distribution at the perimeter of gas turbine installations in the low and medium frequency ranges. Most of the high noise frequency range is between 250 Hz and 2 kHz for source, path, and receiver. All acquired values are compared to the Department of Safety and Health (Occupational Safety and Health (Noise Exposure) Regulations 2019 in Malaysia. As a result, oil and gas service operators can monitor and take countermeasures to limit noise exposure at oil and gas facilities.

Effects of 75 dB, 16 kHz Octave Band Sound Exposure on Physiological and Behavioral Variables in Rats

1995 ◽  
Author(s):  
Gail J. Nakamura ◽  
Gary Mele ◽  
Sujata Naidu ◽  
Steve Hing ◽  
Charles S. Rebert ◽  
...  
Keyword(s):  
Octave Band ◽  
Sound Exposure ◽  
Behavioral Variables

Development of an Engine System Model for Predicting Structural Vibration

1995 ◽  
Author(s):  
S. H. Sung ◽  
D. J. Nefske
Keyword(s):  
Finite Element ◽  
Narrow Band ◽  
Vibration Response ◽  
System Model ◽  
Structural Vibration ◽  
Octave Band ◽  
Engine System ◽  
Excitation Frequencies ◽  
Engine Components ◽  
Structural Mass

Abstract A finite-element based engine system model is developed for predicting the structural vibration of the engine. The engine system model combines modal models of the major bolted-together sub-structures of the engine, with non-structural mass models of the remaining engine components added to bring the inertial properties to those of the running engine. The model is developed and experimentally evaluated with impact and shaker excitation tests. Comparisons are made of the predicted and measured vibration response for various partially assembled engine configurations, as well as for the fully assembled engine. The comparisons illustrate the accuracy of the model in predicting the narrow-band and one-third octave-band vibration response for excitation frequencies up to 2 kHz.

Sign in / Sign up

Export Citation Format

Share Document