The reduction in noise levels on-site recreation facilities using methods of shielding

2016 ◽  
Vol 1 (61) ◽  
pp. 186-189
Author(s):  
Anna Petrova ◽  
1976 ◽  
Vol 19 (2) ◽  
pp. 216-224 ◽  
Author(s):  
James T. Yates ◽  
Jerry D. Ramsey ◽  
Jay W. Holland

The purpose of this study was to compare the damage risk of 85 and 90 dBA of white noise for equivalent full-day exposures. The damage risk of the two noise levels was determined by comparing the temporary threshold shift (TTS) of 12 subjects exposed to either 85 or 90 dBA of white noise for equivalent half- and full-day exposures. TTS was determined by comparing the pre- and postexposure binaural audiograms of each subject at 1, 2, 3, 4, 6, and 8 kHz. It was concluded that the potential damage risk, that is, hazardous effect, of 90 dBA is greater than 85 dBA of noise for equivalent full-day exposures. The statistical difference between the overall effects of equivalent exposures to 85 dBA as compared to 90 dBA of noise could not be traced to any one frequency. The damage risk of a full-day exposure to 85 dBA is equivalent to that of a half-day exposure to 90 dBA of noise. Within the limits of this study, TTS t was as effective as TTS 2 for estimating the damage risk of noise exposure.


2010 ◽  
Vol 35 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Wojciech Batko ◽  
Bartosz Przysucha

AbstractAssessment of several noise indicators are determined by the logarithmic mean <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P42524002G141TV8_html\05_paper.gif" alt=""/>, from the sum of independent random resultsL1;L2; : : : ;Lnof the sound level, being under testing. The estimation of uncertainty of such averaging requires knowledge of probability distribution of the function form of their calculations. The developed solution, leading to the recurrent determination of the probability distribution function for the estimation of the mean value of noise levels and its variance, is shown in this paper.


Author(s):  
Herni Halim ◽  
◽  
Nur Fatin Najiyah Hamid ◽  
Mohamad Firdaus Mahamad Yusob ◽  
Nur Atiqah Mohamad Nor ◽  
...  

2017 ◽  
Vol 73 (2) ◽  
Author(s):  
Eray Yurtseven ◽  
Merve Bosat ◽  
Selcuk Koksal ◽  
Suphi Vehid ◽  
Cemıle Nihal Yurtseven

2020 ◽  
Vol 8 (4) ◽  
pp. 47-59
Author(s):  
Iheanyichukwu M. Elechi

The purpose of this study was to investigate the relationship between the aircraft noise exposure, annoyance reactions and health status of the residents living within the vicinity of the Murtala Muhammed International Airport (MMA) in Lagos state, Nigeria. Aircraft noise monitoring was conducted in five locations within the vicinity (0-5Km) of MMA, and a sixth distant location (14km away). Levels of aircraft noise for all five locations within the vicinity of the airport exceeded the EPA Victoria threshold of 75 dB LAmax for the residential area (outdoor). A survey on annoyance induced by aircraft noise exposure and general health status was conducted on 450 local residents in the study locations using the International Commission on Biological Effect of Noise question and a single question that has been applied in Dutch national health care surveys since 1983 on self-reported general health status respectively. Percentage of residents within the vicinity of MMA that were highly annoyed (%HA) exceeded 15% guideline limit stipulated by Federal Interagency Committee on Urban Noise while 14.5% reported poor health status. There was a significant association between the annoyance reactions and aircraft noise levels in the study locations while the association between self-reported health status and aircraft noise levels was not significant. Taken together, the residents within the vicinity of the airport are exposed to aircraft noise levels above permissible limit which may be associated with high annoyance reaction but may not be associated with poor health rating. Evidence-based aircraft noise related policies by government are advocated.


Author(s):  
Philip James

Elements of the physical aspects of urban environments determine which micro-organisms, plants, and animals live in urban environments. In this chapter, climate, air, water, soil, noise, and light are discussed. Urban environments are affected by the climate of the region in which they are located, and in turn and create their own, distinctive urban climate. Air, water, and soil are all affected by urbanization. Pollution of these elements is common. High noise levels and artificial light at night (ALAN—a new phenomenon) are both strongly associated with urban environments. Details of both are discussed. The discussion in this chapter provides a foundation for further exploration of the diversity of life in urban environments and for later exploration of how organisms adapt to urban living, which will be discussed in Parts II and III.


2019 ◽  
Vol 73 (12) ◽  
pp. 1436-1450 ◽  
Author(s):  
Fabiola León-Bejarano ◽  
Martin O. Méndez ◽  
Miguel G. Ramírez-Elías ◽  
Alfonso Alba

A novel method based on the Vancouver Raman algorithm (VRA) and empirical mode decomposition (EMD) for denoising Raman spectra of biological samples is presented. The VRA is one of the most used methods for denoising Raman spectroscopy and is composed of two main steps: signal filtering and polynomial fitting. However, the signal filtering step consists in a simple mean filter that could eliminate spectrum peaks with small intensities or merge relatively close spectrum peaks into one single peak. Thus, the result is often sensitive to the order of the mean filter, so the user must choose it carefully to obtain the expected result; this introduces subjectivity in the process. To overcome these disadvantages, we propose a new algorithm, namely the modified-VRA (mVRA) with the following improvements: (1) to replace the mean filter step by EMD as an adaptive parameter-free signal processing method; and (2) to automate the selection of polynomial degree. The denoising capabilities of VRA, EMD, and mVRA were compared in Raman spectra of artificial data based on Teflon material, synthetic material obtained from vitamin E and paracetamol, and biological material of human nails and mouse brain. The correlation coefficient (ρ) was used to compare the performance of the methods. For the artificial Raman spectra, the denoised signal obtained by mVRA ([Formula: see text]) outperforms VRA ([Formula: see text]) for moderate to high noise levels whereas mVRA outperformed EMD ([Formula: see text]) for high noise levels. On the other hand, when it comes to modeling the underlying fluorescence signal of the samples (i.e., the baseline trend), the proposed method mVRA showed consistent results ([Formula: see text]. For Raman spectra of synthetic material, good performance of the three methods ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA) was obtained. Finally, in the biological material, mVRA and VRA showed similar results ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA); however, mVRA retains valuable information corresponding to relevant Raman peaks with small amplitude. Thus, the application of EMD as a filter in the VRA method provides a good alternative for denoising biological Raman spectra, since the information of the Raman peaks is conserved and parameter tuning is not required. Simultaneously, EMD allows the baseline correction to be automated.


Sign in / Sign up

Export Citation Format

Share Document