A comparison of standardized methods for sound attenuation test of hearing protectors

2021 ◽  
Vol 263 (1) ◽  
pp. 5187-5196
Author(s):  
Sakae Yokoyama
Keyword(s):  
Evaluation Methods ◽  
Measurement Methods ◽  
Sound Attenuation ◽  
International Standards ◽  
Occupational Noise ◽  
Noisy Environment ◽  
Hearing Protectors ◽  
Measurement And Evaluation ◽  
Product Standard ◽  
First Time

In order to prevent hearing impairment due to occupational noise, it is essential to wear hearing protectors such as earplugs and earmuffs, especially in an extremely noisy environment. The method of measuring their sound attenuation is defined by international standards such as ISO and IEC, and standards such as ANSI, BS, AS/NZS, JIS et.. Although most standards recommend subjective methods where the thresholds of hearing shall be measured once with open ears and once with the hearing protector in place for each subject, measurement and evaluation methods are not unified internationally. In Japan, in April 2020, the old product standard was abolished in consideration of international consistency, and a new method standard was established with the ISO standard as the corresponding international standard for the first time in about 40 years. In this study, we compared the measurement methods and evaluation methods according to the standards for sound attenuation tests of hearing protectors.

scholarly journals Comparison of harmonic limits and evaluation of the international standards

2019 ◽  
Vol 277 ◽  
pp. 03009
Author(s):  
Zijiang WANG ◽  
Qionglin LI ◽  
Yuzheng TANG ◽  
Shuming LIU ◽  
Shuangyin DAI
Keyword(s):  
Evaluation Methods ◽  
International Standards ◽  
Processing Methods ◽  
The Difference ◽  
Chinese Standard

The paper takes the Chinese standard GB/T 14549-1993, the British Engineering Recommendation G5/4-1, the Institute of Electrical and Electronics Engineers IEEE Std 519-2014 and the part of IEC 61000-3 series standard as an example. Then summarize the difference of harmonic limits, the different processing methods of harmonic impedance, and the different summation law of each standard. Compare the harmonic limit calculation and evaluation methods of Chinese GB/T 14549-1993, British G5/4-1 and IEEE Std 519-2014 standard in detail, summarize the characteristics of the three standards in disturbance emission evaluation and introduce examples to verify the conclusion. Finally, summarize the characteristics and differences of mentioned harmonic standards.

scholarly journals Measurement of Earmuffs Attenuation at High Audible Frequencies

2017 ◽  
Vol 42 (2) ◽  
pp. 249-254
Author(s):  
Emil Kozłowski ◽  
Rafał Młyński
Keyword(s):  
Frequency Band ◽  
Measurement Method ◽  
Sound Attenuation ◽  
The Other ◽  
Hearing Protection ◽  
Noise Attenuation ◽  
Frequency Range ◽  
Test Fixture ◽  
Hearing Protectors ◽  
Audible Frequency

Abstract Standardised measurements of sound attenuation of hearing protectors are performed in the frequency range from 125 Hz to 8 kHz. However, noise present at many workplaces contains significant components at higher audible frequency. Therefore, the knowledge about noise attenuation with earmuffs in the audible frequency range above 8 kHz is also necessary for proper hearing protection. The aim of this study was to obtain values of the noise attenuation with 27 commonly-used earmuffs models in the 1/3 octave bands of 10, 12.5 and 16 kHz. The measurements were conducted with a real ear at threshold (REAT) method with participation of subjects. The study showed that attenuation of earmuffs ranged from 24.7 to 42.8 dB, depending on model of earmuffs and frequency band. Furthermore, the measurements were performed with the use of acoustic test fixture which is designed especially for testing hearing protectors. Results obtained with the use of acoustic test fixture indicated that this measurement method can lead to values close to attenuation measured with participation of subjects. On the other hand, values obtained with the use of acoustic test fixture may differ average up to 14 dB from REAT method.

scholarly journals Video-based motion-resilient reconstruction of 3D position for fNIRS and EEG head mounted probes

2019 ◽  
Author(s):  
Sagi Jaffe-Dax ◽  
Amit H. Bermano ◽  
Yotam Erel ◽  
Lauren L. Emberson
Keyword(s):  
State Of The Art ◽  
Measurement Methods ◽  
Fast Method ◽  
Single Measurement ◽  
Extensive Training ◽  
Neuroimaging Data ◽  
Fast Motion ◽  
Scalp Location ◽  
First Time ◽  
Machine Learning Tool

AbstractSignificanceWe propose a novel video-based, motion-resilient, and fast method for estimating the position of optodes on the scalp.AimMeasuring the exact placement of probes (e.g., electrodes, optodes) on a participant’s head is a notoriously difficult step in acquiring neuroimaging data from methods which rely on scalp recordings (e.g., EEG and fNIRS), and is particularly difficult for any clinical or developmental population. Existing methods of head measurements require the participant to remain still for a lengthy period of time, are laborious, and require extensive training. Therefore, a fast and motion-resilient method is required for estimating the scalp location of probes.ApproachWe propose an innovative video-based method for estimating the probes’ positions relative to the participant’s head, which is fast, motion-resilient, and automatic. Our method builds on capitalizing the advantages, and understanding the limitations, of cutting-edge computer vision and machine learning tool. We validate our method on 10 adult subjects and provide proof of feasibility with infant subjects.ResultsWe show that our method is both reliable and valid compared to existing state-of-the-art methods by estimating probe positions in a single measurement, and by tracking their translation and consistency across sessions. Finally, we show that our automatic method is able to estimate the position of probes on an infant head without lengthy offline procedures, a task which is considered challenging until now.ConclusionsOur proposed method allows, for the first time, the use of automated spatial co-registration methods on developmental and clinical populations, where lengthy, motion-sensitive measurement methods routinely fail.

scholarly journals “Technical interoperability”: ISO/TC46/SC4 annual meeting

2020 ◽  
pp. 183-192
Author(s):  
I. V. Timoshenko
Keyword(s):  
Annual Meeting ◽  
Information Science ◽  
International Standards ◽  
Document Management ◽  
Science Standards ◽  
Plenary Meeting ◽  
Wide Range ◽  
Working Groups ◽  
Key Events ◽  
First Time

The author reviews the key events and projects held and discussed within the framework of the ISO/TC46/SC4 plenary meeting. The meeting was held as part of the 47th annual ISO/TC46 meeting week held in London 2020. The subject scope of ISO/TC46 covers a wide range of issues related to document management, indexing and abstracting services, and information science. Due to COVID19 pandemic, all the meetings were moved to online. The committee’s annual meeting was held in this format for the first time. The subcommittees and working groups discussed issues related to international standardization and ongoing projects in this area. The author discusses in detail the presentations by the participants in the plenary meeting ISO/TC46/SC4, held on May 12, 2020. The ISO/TC46/SC4 subcommittee conducts a number of projects to ensure the technical compatibility of library information systems with information science standards in related fields, which are developed by other ISO Technical Committees, as well as other authoritative organizations, i.e. DCMI and W3C. At ISO/TC46/SC4 plenary meeting, the working groups’ chairs reported on the state of the art in corresponding projects of international standards, plans for future were discussed. Subcommittee’s internal activities as well as issues of cooperation with other organizations were also covered.

scholarly journals A talajok aggregátum-stabilitásának vizsgálati lehetőségei I. Makroaggregátum-stabilitás

2021 ◽  
Vol 70 (1) ◽  
pp. 87-109
Author(s):  
Labancz Viktória ◽  
Barna Gyöngyi ◽  
Szegi Tamás ◽  
Makó András
Keyword(s):  
Standard Method ◽  
Scientific Literature ◽  
Aggregate Stability ◽  
Evaluation Methods ◽  
Destructive Effect ◽  
Measurement And Evaluation ◽  
The Stability ◽  
Stability Measurements ◽  
Different Soils

A makroaggregátumok stabilitásának meghatározására számos mérési módszer és értékelési lehetőség létezik. Ezek önállóan eredményesen alkalmazhatók az aggregátumok stabilitásának vizsgálatára (valamilyen romboló hatást megpróbálnak szimulálni, valamilyen körülményt megpróbálnak standardizálni stb.), ám ezek a módszerek egymással nehezen összevethetők. Az évek során jogosan merült fel a szabványosítás igénye, ám a kialakult nemzetközi szabvány módszertana igen bonyolult, éppen ezért csak kevesen kívánják azt alkalmazni. Hasonló a helyzet a különféle stabilitási mutatók esetében is: sokféle mutató használatos, ezek különkülön jól jellemezhetik a talajok aggregátum-stabilitását, de a mutatók párhuzamos használata több esetben eltérő stabilitási sorrendet eredményez a különféle talajoknál. Megfelelő megoldás lehetne, ha definiálni tudnánk, hogy mely módszer és mely mutató pontosan mit is fejez ki és mikor, milyen probléma vizsgálatakor, mely mutatót és mely módszert kívánatos alkalmazni. Kutatásainkat a továbbiakban ilyen irányban is folytatni kívánjuk.There are several measurement and evaluation methods for determining the stability of macro-aggregates. These can be used effectively independently to test the stability of aggregates (attempting to simulate some destructive effect, attempting to standardise some condition, etc.), but they are difficult to compare to each other. Over the years, the need for standardization has rightly arisen, but the standard method developed is very complicated, which is why few people want to apply it.Similarly, many different indicators are used, each of which can give a good characterisation of the aggregate stability of soils, but the parallel use of indicators often results in different stability rankings for different soils. An appropriate solution should be defined which method and which indicator expresses what exactly and when, and which indicator and which method should be used for which problem. We intend to continue our research in this direction.In this manuscript we summarized the main macro-aggregate stability measurements and indices, reviewed the international and Hungarian scientific literature.

scholarly journals Measurement and evaluation methods for damage of fibers from dry sand erosion in a hot environment

2012 ◽  
Vol 82 (15) ◽  
pp. 1612-1617 ◽  
Author(s):  
Limin Bao ◽  
Dongling Li ◽  
Danna Qian ◽  
Kiyoshi Kemmochi ◽  
Atsuhiko Yamanaka
Keyword(s):  
Evaluation Methods ◽  
Hot Environment ◽  
Sand Erosion ◽  
Dry Sand ◽  
Measurement And Evaluation

Examination of CPT-Based Liquefaction Evaluation Methods for New Zealand Earthquake

2013 ◽  
Vol 477-478 ◽  
pp. 1105-1108
Author(s):  
Tong Zhi Chen ◽  
Xiao Ming Yuan
Keyword(s):  
New Zealand ◽  
Test Data ◽  
Historical Earthquakes ◽  
Evaluation Methods ◽  
Field Investigation ◽  
The Other ◽  
Success Rates ◽  
In Situ Test ◽  
First Time

On February 22, 2011 a MW6.2 earthquake struck Christchurch in New Zealand, which is the first time that liquefaction acts as the main cause of damage since there is survey record of historical earthquakes. On the basis of field investigation and in-situ test data, domestic and foreign liquefaction evaluation methods based on CPT including Chinese code, Robertson and Olsen methods are examined and their applicability and reliability are assessed. Analysis shows that the method adopted in Chinese code is more dangerous, whose success rates of liquefaction and non-liquefaction evaluation are 70% and 94%.The other two methods abroad are severely conservative, for the success rates of liquefaction and non-liquefaction evaluation of Robertson method are 100% and 40%, and Olsen method 100% and 11% respectively. Liquefaction evaluation methods need further research to be improved.

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