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    Tytuł:
    Statistical investigations of fast changeable processes occurring in ship piston combustion engine
    Autorzy:
    Chłopek, Z.
    Piaseczny, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/259250.pdf
    Data publikacji:
    2005
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    piston combustion engine
    fast changeable processes
    stochastic processes
    high frequency noise
    Opis:
    Combustion piston engine is one of the devices in which fast changeable processes occur in operational conditions. In this paper are presented basic problems associated with research on fast changeable processes occurring in diesel engines, exemplified by the processes of indicated pressure and fuel pressure injected to engine's cylinder. Dynamical characteristics of the investigated processes were analyzed and problems of synchronous averaging of pseudo-periodical signals were considered in order to limit high frequency noise content in useful signal. Some limitations of elimination effectiveness of high frequency noise from tested signals have been revealed.
    Źródło:
    Polish Maritime Research; 2005, 2; 10-16
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Eliminacja zakłóceń topografii powierzchni cylindrów silników spalinowych z zastosowaniem Transformaty Falkowej Pochodnych Gaussowskich
    The high-frequency noise removal from the surface topography of cylinder liners using Differential of Gaussian Wavelet
    Autorzy:
    PODULKA, Przemysław
    Powiązania:
    https://bibliotekanauki.pl/articles/457934.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Rzeszowski
    Tematy:
    topografia powierzchni
    Transformata Falkowa
    zakłócenia wysokoczęstotliwościowe
    metrologia powierzchni
    surface topography
    wavelet transform
    high-frequency noise
    surface metrology
    Opis:
    W pracy przedstawiono procedurę eliminacji zakłóceń pomiarowych ze struktury geometrycznej powierzchni elementów silników spalinowych. Badano powierzchnie cylindrów po gładzeniu płasko-wierzchołkowym oraz po wygniataniu kieszeni olejowych. Analizowano parametry z normy ISO-25178. Do rozwiązania problemu zastosowano Transformatę Falkową Pochodnych Gaussowskich. Określono także wpływ wyników badań na postępy w edukacji z zakresu metrologii.
    In this article the removal of high-frequency noise from the surface topography of cylinder liners was presented. The plateau-honed cylinders as well as cylinder liners with additionally added oil pockets were analysed and the parameters from ISO-25178 standard were processed. The Differential of Gaussian Wavelet was used as the possibility of problem solution. The influence of obtained results on metrology education was also found.
    Źródło:
    Edukacja-Technika-Informatyka; 2014, 5, 1; 669-675
    2080-9069
    Pojawia się w:
    Edukacja-Technika-Informatyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Noise Hazard Assessment within the Intermediate Range of the High Audible and the Low Ultrasonic Frequencies
    Autorzy:
    Śliwiński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/177315.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasonic noise assessment
    high frequency audiometry
    Opis:
    In parallel to the ultrasonic noise assessment procedures and research activity in the field there have appeared several papers in the domain of so called high-frequency audiometry which covers the range of frequencies 8–20 kHz. They are important for recognizing the harmfulness and hazard of the audible high frequency sound components in the same range as the one of the low frequency ultrasonic noise. On the other hand there exists a certain inconsequent situation in the general approach to the problem of ultrasonic noise hazard assessment in work places environment which concerns the convention to include the frequency range of 10–20 kHz to the domain of ultrasonics. The range consists of one third octave bands of central frequencies: 10, 12.5, 16, 20 kHz and conventionally is called low frequency ultrasonic noise though at least the components of the two lowest bands are naturally audible by a majority of population (mainly young people).The paper presents a discussion related to some achievements of the two domains and some conclusions which could be useful for a more consequent description of the subject and could be taken into account in the future regulations for the ultrasonic noise assessment in work places environment.
    Źródło:
    Archives of Acoustics; 2016, 41, 2; 331-338
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hearing status of people occupationally exposed to ultrasonic noise
    Autorzy:
    Dudarewicz, Adam
    Zamojska-Daniszewska, Małgorzata
    Zaborowski, Kamil
    Pawlaczyk-Łuszczyńska, Małgorzata
    Powiązania:
    https://bibliotekanauki.pl/articles/2084911.pdf
    Data publikacji:
    2022-06-08
    Wydawca:
    Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
    Tematy:
    noise
    pure-tone audiometry
    otoacoustic emissions
    noise-induced hearing loss
    ultrasonic noise
    extended high-frequency audiometry
    Opis:
    ObjectivesThe aim of the study was to evaluate the hearing status of operators of low-frequency ultrasonic devices compared to employees exposed to audible noise at a similar A-weighted sound pressure level (SPL) but without ultrasonic components.Material and MethodsStandard pure-tone audiometry, extended high-frequency audiometry (EHFA), transient-evoked otoacoustic emissions (TEOAE), and distortion-product otoacoustic emissions (DPOAE), as well as questionnaire surveys were conducted among 148 subjects, aged 43.1±10.8 years, working as ultrasonic device operators for 18.7±10.6 years. Their exposure to noise within the ultrasonic and audible frequency range was also evaluated. The control group comprised 168 workers, adjusted according to gender, age (±2 years), tenure (±2 years), and the 8-hour daily noise exposure level (LEX,8h) of ±2 dB.ResultsThe ultrasonic device operators and the control group were exposed to audible noise at LEX,8h of 80.8±3.9 dB and 79.1±3.4, respectively. The Polish maximum admissible intensity (MAI) values for audible noise were exceeded in 16.8% of the ultrasonic device operators, while 91.2% of them were exposed to ultrasonic noise at SPL>MAI values. There were no significant differences between the groups in terms of the hearing threshold levels (HTLs) up to 3 kHz, while the ultrasonic device operators exhibited significantly higher (worse) HTLs, as compared to the control group, in the range of 4–14 kHz. The results of the DPOAE and TEOAE testing also indicated worse hearing among the ultrasonic device operators. However, the differences between the groups were more pronounced in the case of EHFA and DPOAEs.ConclusionsThe outcomes of all hearing tests consistently indicated worse hearing among the ultrasonic device operators as compared to the control group. Both EHFA and DPOAE seem to be useful tools for recognizing early signs of hearing loss among ultrasonic device operators.
    Źródło:
    International Journal of Occupational Medicine and Environmental Health; 2022, 35, 3; 309-325
    1232-1087
    1896-494X
    Pojawia się w:
    International Journal of Occupational Medicine and Environmental Health
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hydrodynamic analysis of noise propagation by the high skew marine propeller working in non-uniform inflow
    Autorzy:
    Hadipour, A.
    Abadi, K. A. V.
    Khanzadi, H.
    Motahari, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839886.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    hałas
    wahania ciśnienia
    śmigło
    noise
    high skew marine propeller
    pressure fluctuating
    blade passing frequency
    Opis:
    Being able to predict ship and marine propulsion noise is an important issue for naval architectures and the international maritime community. The main objective of this paper is the numerical investigation on the noise propagation by the high skew marine propeller working in a non-uniform inflow via RANS solver in the broadband frequency range. The pressure fluctuations were monitored at three points on the propeller blade, then by using the FFT operator we computed the blade passing frequency (BPF) for different propeller loading conditions. Based on these pressure pulses and adopting the Fowcs Williams-Hawking model we calculated noise radiated at the monitoring points. The results showed the BPF and noise level increased by increasing the load on the blades and we also observed that the noise generated at the leading edge was greater than at other points. Furthermore, the study of pressure fluctuations showed the propeller tip has more pressure variations in one revolution than other regions of the propeller surface.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 1; 104-121
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Noise exposure and hearing status among employees using communication headsets
    Autorzy:
    Pawlaczyk-Łuszczyńska, Małgorzata
    Dudarewicz, Adam
    Zaborowski, Kamil
    Zamojska-Daniszewska, Małgorzata
    Powiązania:
    https://bibliotekanauki.pl/articles/2153012.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
    Tematy:
    noise-induced hearing loss
    pure-tone audiometry
    otoacoustic emissions
    communication headsets
    occupational exposure to noise
    extended high-frequency audiometry
    Opis:
    Objectives The objective of this study was to assess the hearing of employees using communication headsets with regard to their exposure to noise. Material and Methods The study group comprised 213 employees, including 21 workers of the furniture industry, 15 court transcribers and 177 call center operators, aged 19–55 years, working with headsets for a period of up to 25 years. All the participants underwent a standard puretone audiometry, extended high-frequency audiometry (EHFA) as well as transient-evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs). Noise exposure from headsets was evaluated using the microphone in a real ear technique according to PN-EN ISO 11904-1:2008. Results Personal daily noise exposure levels ranged 57–96 dB and exceeded 85 dB only in 1.4% of the call center operators. Forty-two percent of the participants had bilateral normal hearing in the standard frequency range of 250–8000 Hz, and 33% in the extended highfrequency range of 9–16 kHz. It was found that DPOAEs were present bilaterally in 59% of the participants. Reproducibility of TEOAE at >70% and signal-to-noise ratio at >6 was exhibited by 42% and 17% of them, respectively. The 3 subgroups of workers differed in age, gender, noise exposure and type of headsets in use. However, after adjusting for age and gender, significant differences between these subgroups in terms of hearing were mostly visible in EHFA. A significant impact of age, gender, daily noise exposure level and current job tenure on hearing tests results was also noted among the call center operators and the transcribers. The most pronounced were the effects of age and gender, whereas the impact of the daily noise exposure level was less evident. Conclusions It seems that EHFA is useful for recognizing early signs of noise-induced hearing loss among communication headset users. However, further studies are needed before any firm conclusions concerning the risk of hearing impairment due to the use of such devices can be drawn.
    Źródło:
    International Journal of Occupational Medicine and Environmental Health; 2022, 35, 5; 585-614
    1232-1087
    1896-494X
    Pojawia się w:
    International Journal of Occupational Medicine and Environmental Health
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exposure to excessive sounds and hearing status in academic classical music students
    Autorzy:
    Pawlaczyk-Łuszczyńska, Małgorzata
    Zamojska-Daniszewska, Małgorzata
    Dudarewicz, Adam
    Zaborowski, Kamil
    Powiązania:
    https://bibliotekanauki.pl/articles/2161930.pdf
    Data publikacji:
    2017-02-21
    Wydawca:
    Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
    Tematy:
    noise-induced hearing loss
    music students
    exposure to excessive sounds
    pure-tone audiometry
    hearing threshold levels
    high-frequency notches
    Opis:
    Objectives The aim of this study was to assess hearing of music students in relation to their exposure to excessive sounds. Material and Methods Standard pure-tone audiometry (PTA) was performed in 168 music students, aged 22.5±2.5 years. The control group included 67 subjects, non-music students and non-musicians, aged 22.8±3.3 years. Data on the study subjects’ musical experience, instruments in use, time of weekly practice and additional risk factors for noise-induced hearing loss (NIHL) were identified by means of a questionnaire survey. Sound pressure levels produced by various groups of instruments during solo and group playing were also measured and analyzed. The music students’ audiometric hearing threshold levels (HTLs) were compared with the theoretical predictions calculated according to the International Organization for Standardization standard ISO 1999:2013. Results It was estimated that the music students were exposed for 27.1±14.3 h/week to sounds at the A-weighted equivalent-continuous sound pressure level of 89.9±6.0 dB. There were no significant differences in HTLs between the music students and the control group in the frequency range of 4000–8000 Hz. Furthermore, in each group HTLs in the frequency range 1000–8000 Hz did not exceed 20 dB HL in 83% of the examined ears. Nevertheless, high frequency notched audiograms typical of the noise-induced hearing loss were found in 13.4% and 9% of the musicians and non-musicians, respectively. The odds ratio (OR) of notching in the music students increased significantly along with higher sound pressure levels (OR = 1.07, 95% confidence interval (CI): 1.014–1.13, p < 0.05). The students’ HTLs were worse (higher) than those of a highly screened non-noise-exposed population. Moreover, their hearing loss was less severe than that expected from sound exposure for frequencies of 3000 Hz and 4000 Hz, and it was more severe in the case of frequency of 6000 Hz. Conclusions The results confirm the need for further studies and development of a hearing conservation program for music students. Int J Occup Med Environ Health 2017;30(1):55–75
    Źródło:
    International Journal of Occupational Medicine and Environmental Health; 2017, 30, 1; 55-75
    1232-1087
    1896-494X
    Pojawia się w:
    International Journal of Occupational Medicine and Environmental Health
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tinnitus Therapy Based on High-Frequency Linearization Principles - Preliminary Results
    Autorzy:
    Poremski, T.
    Kostek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/177726.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    tinnitus
    sensorineural hearing loss
    tinnitus masking
    Tinnitus Retraining Therapy (TRT)
    signal quantization
    dithering technique
    high-frequency linearization
    ultrasound dither noise
    Opis:
    The aim of this work is to present problems related to tinnitus symptoms, its pathogenesis, hypothe- ses on tinnitus causes, and therapy treatment to reduce or mask the phantom noise. In addition, the hypothesis on the existence of parasitic quantization that accompanies hearing loss has been recalled. Moreover, the paper describes a study carried out by the Authors with the application of high-frequency dither having specially formed spectral characteristics. Discussion on preliminary results obtained and conclusions are also contained.
    Źródło:
    Archives of Acoustics; 2012, 37, 2; 161-170
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Challenges for 10 nm MOSFET process integration
    Autorzy:
    Östling, M.
    Malm, B. G.
    Haartman, M.
    Hallstedt, J.
    Zhang, Z.
    Hellström, P. E.
    Zhang, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/309004.pdf
    Data publikacji:
    2007
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    sstrained silicon
    silicon-germanium
    silicon-on-insulator (SOI)
    high-k dielectrics
    hafnium oxide
    nanowire
    low frequency noise
    mobility
    metal gate
    Opis:
    An overview of critical integration issues for future generation MOSFETs towards 10 nm gate length is presented. Novel materials and innovative structures are discussed. The need for high-k gate dielectrics and a metal gate electrode is discussed. Different techniques for strain-enhanced mobility are discussed. As an example, ultra thin body SOI devices with high mobility SiGe channels are demonstrated.
    Źródło:
    Journal of Telecommunications and Information Technology; 2007, 2; 25-32
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hearing Status in Young People Using Portable Audio Players
    Autorzy:
    Pawlaczyk-Łuszczyńska, M.
    Zaborowski, K.
    Zamojska-Daniszewska, M.
    Rutkowska-Kaczmarek, P.
    Dudarewicz, A.
    Śliwinska-Kowalska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176501.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    portable audio players
    PAPs
    pure-tone audiometry
    transient-evoked otoacoustic emissions
    TEOAEs
    hearing threshold levels
    high-frequency notches
    noise-induced hearing loss
    Opis:
    The aim of this study was to evaluate the hearing status in young adults using portable audio players (PAPs) in relation to their listening habits. The study included 58 subjects, aged 22.8±2.8 years, non-occupationally exposed to noise. Questionnaire inquiry aimed at collecting personal data, the information on PAPs usage habits, self-assessment of hearing status and identification of risk factors for noise-induced hearing loss (NIHL) were performed in study subjects. Hearing tests included pure-tone audiometry (PTA) and transient-evoked optoacoustic emission (TEOAE). All subjects were PAPs users. Depending on listening habits they were divided into the subgroups of “frequent” users (>1 h/day) and “non-frequent” users (≤1 h/day). There were no significant differences between subgroups in prevalence of NIHL risk factors and self-assessment of hearing status. However, frequent users more often complained of tinnitus and hyperacusis. Majority (81.9 %) of participants had normal hearing. Nevertheless, 6.9 % of audiograms showed high-frequency notches typical for NIHL. Both, the PTA and TEOAE indicated worse hearing in non-frequent users compared to frequent users. No significant differences in prevalence of high-frequency notches between subgroups were noted. The outcomes do not support some previous studies results that the excessive exposure to music listened through PAPs might result in accelerating of development of NIHL loss in young adults.
    Źródło:
    Archives of Acoustics; 2017, 42, 1; 113-120
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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