Study on water boiling noises in a large volume

International Nuclear Information System (INIS)

Masagutov, R.F.; Krivtsov, V.A.

1977-01-01

Presented are the results of measurement of the noise spectra during boiling of water in a large volume at the pressure of 1 at. Boiling of the distilled water has been accomplished with the use of the heaters made of the Kh18N10T steel, 50 mm in length, 2 mm in the outside diameter, with the wall thickness of 0.1 mm. The degree of water under heating changed during the experiments from 0 to 80 deg C, and the magnitude of the specific heat flux varied from o to 0.7 - 0.9 qsup(x), where qsup(x) was the specific heat flux of the tube burn-out. The noise spectrum of the boiling water was analyzed at frequencies of 0.5 to 200 kHz. The submerge-type pressure-electric transmitters were used for measurements. At underheating boiling during the experiment the standing waves have formed which determine the structure of the measured spectra. During saturated boiling of water no standing waves were revealed. At underheating over 15 - 20 deg C the water boiling process is accompanied by the noises within the ultrasonic frequency range. The maximum upper boundary of the noise in the experiments amounts to 90 - 100 kHz

Risk factor noise - otological aspects

Energy Technology Data Exchange (ETDEWEB)

Haas, E

1984-06-11

After a short review of the anatomy and physiology of the inner ear the pathogenesis of chronic noise-induced hearing loss is discussed. The exposure to noise results first in a temporary but reversible threshold shift. But if the exposure to noise was exceedingly high or if the rest period would have required further noise reduction, a state of so-called auditory fatigue develops, finally leading to noise-induced hearing loss, a state which is considered irreversible. The noise-perception varies greatly among individuals and thus it is impossible to determine a certain noise intensity above which noise leasions will to be expected. It is generally accepted, that longterm exposure to noise above 85 dB (A) may lead to hearing loss in a portion of the exposed persons.

Impact of noise and other factors on speech recognition in anaesthesia

DEFF Research Database (Denmark)

Alapetite, Alexandre

2008-01-01

of training. Methods: Eight volunteers read aloud a total of about 3 600 typical short anaesthesia comments to be transcribed by a continuous speech recognition system. Background noises were collected in an operating room and reproduced. A regression analysis and descriptive statistics were done to evaluate...... operations. Objective: The aim of the experiment is to evaluate the relative impact of several factors affecting speech recognition when used in operating rooms, such as the type or loudness of background noises, type of microphone, type of recognition mode (free speech versus command mode), and type...... the relative effect of various factors. Results: Some factors have a major impact, such as the words to be recognised, the type of recognition, and participants. The type of microphone is especially significant when combined with the type of noise. While loud noises in the operating room can have a predominant...

Effects of large pressure amplitude low frequency noise in the parotid gland perivasculo-ductal connective tissue.

Science.gov (United States)

Oliveira, Pedro; Brito, José; Mendes, João; da Fonseca, Jorge; Águas, Artur; Martins dos Santos, José

2013-01-01

In tissues and organs exposed to large pressure amplitude low frequency noise fibrosis occurs in the absence of inflammatory signs, which is thought to be a protective response. In the parotid gland the perivasculo-ductal connective tissue surrounds arteries, veins and the ductal tree. Perivasculo-ductal connective tissue is believed to function as a mechanical stabilizer of the glandular tissue. In order to quantify the proliferation of perivasculo-ductal connective tissue in large pressure amplitude low frequency noise-exposed rats we used sixty Wistar rats which were equally divided into 6 groups. One group kept in silence, and the remaining five exposed to continuous large pressure amplitude low frequency noise: g1-168h (1 week); g2-504h (3 weeks); g3-840h (5 weeks); g4-1512h (9 weeks); and g5-2184h (13 weeks). After exposure, parotid glands were removed and the perivasculo-ductal connective tissue area was measured in all groups. We applied ANOVA statistical analysis, using SPSS 13.0. The global trend is an increase in the average perivasculo-ductal connective tissue areas, that develops linearly and significantly with large pressure amplitude low frequency noise exposure time (p connective tissue. Hence, these results show that in response to large pressure amplitude low frequency noise exposure, rat parotid glands increase their perivasculo-ductal connective tissue.

Noise removal using factor analysis of dynamic structures: application to cardiac gated studies.

Science.gov (United States)

Bruyant, P P; Sau, J; Mallet, J J

1999-10-01

Factor analysis of dynamic structures (FADS) facilitates the extraction of relevant data, usually with physiologic meaning, from a dynamic set of images. The result of this process is a set of factor images and curves plus some residual activity. The set of factor images and curves can be used to retrieve the original data with reduced noise using an inverse factor analysis process (iFADS). This improvement in image quality is expected because the inverse process does not use the residual activity, assumed to be made of noise. The goal of this work is to quantitate and assess the efficiency of this method on gated cardiac images. A computer simulation of a planar cardiac gated study was performed. The simulated images were added with noise and processed by the FADS-iFADS program. The signal-to-noise ratios (SNRs) were compared between original and processed data. Planar gated cardiac studies from 10 patients were tested. The data processed by FADS-iFADS were subtracted to the original data. The result of the substraction was studied to evaluate its noisy nature. The SNR is about five times greater after the FADS-iFADS process. The difference between original and processed data is noise only, i.e., processed data equals original data minus some white noise. The FADS-iFADS process is successful in the removal of an important part of the noise and therefore is a tool to improve the image quality of cardiac images. This tool does not decrease the spatial resolution (compared with smoothing filters) and does not lose details (compared with frequential filters). Once the number of factors is chosen, this method is not operator dependent.

Factors Affecting Sentence-in-Noise Recognition for Normal Hearing Listeners and Listeners with Hearing Loss.

Science.gov (United States)

Hwang, Jung Sun; Kim, Kyung Hyun; Lee, Jae Hee

2017-07-01

Despite amplified speech, listeners with hearing loss often report more difficulties understanding speech in background noise compared to normalhearing listeners. Various factors such as deteriorated hearing sensitivity, age, suprathreshold temporal resolution, and reduced capacity of working memory and attention can attribute to their sentence-in-noise problems. The present study aims to determine a primary explanatory factor for sentence-in-noise recognition difficulties in adults with or without hearing loss. Forty normal-hearing (NH) listeners (23-73 years) and thirty-four hearing-impaired (HI) listeners (24-80 years) participated for experimental testing. For both NH and HI group, the younger, middle-aged, older listeners were included. The sentence recognition score in noise was measured at 0 dB signal-to-noise ratio. The ability of temporal resolution was evaluated by gap detection performance using the Gaps-In-Noise test. Listeners' short-term auditory working memory span was measured by forward and backward digit spans. Overall, the HI listeners' sentence-in-noise recognition, temporal resolution abilities, and digit forward and backward spans were poorer compared to the NH listeners. Both NH and HI listeners had a substantial variability in performance. For NH listeners, only the digit backward span explained a small proportion of the variance in their sentence-in-noise performance. For the HI listeners, all the performance was influenced by age, and their sentence-in-noise difficulties were associated with various factors such as high-frequency hearing sensitivity, suprathreshold temporal resolution abilities, and working memory span. For the HI listeners, the critical predictors of the sentence-in-noise performance were composite measures of peripheral hearing sensitivity and suprathreshold temporal resolution abilities. The primary explanatory factors for the sentence-in-noise recognition performance differ between NH and HI listeners. Factors

Environmental Factors Having an Impact on the Noise Induced by Motor Vahicles

Directory of Open Access Journals (Sweden)

Rasa Akelaitytė

2013-12-01

Full Text Available The transport sector is rapidly developing industry in Lithuania. Over the past few years, a significant increase in motor vehicles on our roads can be noticed. Both light and heavy vehicles create economic benefits, and, at the same time, cause ecological and social problems such as noise, a growing number of accidents and environmental pollution. In order to reduce the rate of accidents, many places have been equipped with speed-limiting humps. However, the vehicles approaching them will increase noise levels. The article describes a calculation method of how to determine the influence of various factors caused by car noise. Reflections on the surface, the atmosphere and sound waves on road obstacles can increase or decrease sounds in the environment. The above introduced factors must be taken into account conducting noise measurement tests.Article in Lithuanian

Noise As A Risk Factor In The Preparation Of Useful Mineral Substances

Science.gov (United States)

Irimia, Alin; Sorin, Simion; Pupăzan, Daniel; Călămar, Angela

2015-07-01

Noise from industrial activities is a major problem because of its noxious and its presence in all technological activities. The coal preparation activity from industry, in the presence of risks of exposure to noise, is affecting the health and safety of workers. Occupational hearing loss and deafness caused by exposure to noise at work are the most encountered illnesses occurring in the European Union. This paper examines the main sources of noise in coal preparation technological process and their effects on the human factor.

Low-frequency noise from large wind turbines – additional data and assessment of new Danish regulations

DEFF Research Database (Denmark)

Pedersen, Christian Sejer; Møller, Henrik; Pedersen, Steffen

2012-01-01

turbines in Denmark. In this study, the data material has been increased to include more data on noise from modern production turbines up to 5 MW. In addition, the new Danish regulations are assessed. The previous result that the relative amount of low-frequency noise is higher for large turbines (> 2 MW...... frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors. The new Danish regulation is based...

Empirical formulae for excess noise factor with dead space for single carrier multiplication

KAUST Repository

Dehwah, Ahmad H.

2011-09-01

In this letter, two empirical equations are presented for the calculation of the excess noise factor of an avalanche photodiode for single carrier multiplication including the dead space effect. The first is an equation for calculating the excess noise factor when the multiplication approaches infinity as a function of parameters that describe the degree of the dead space effect. The second equation can be used to find the minimum value of the excess noise factor for any multiplication when the dead space effect is completely dominant, the so called "deterministic" limit. This agrees with the theoretically known equation for multiplications less than or equal to two. © 2011 World Scientific Publishing Company.

Empirical formulae for excess noise factor with dead space for single carrier multiplication

KAUST Repository

Dehwah, Ahmad H.; Ajia, Idris A.; Marsland, John S.

2011-01-01

In this letter, two empirical equations are presented for the calculation of the excess noise factor of an avalanche photodiode for single carrier multiplication including the dead space effect. The first is an equation for calculating the excess noise factor when the multiplication approaches infinity as a function of parameters that describe the degree of the dead space effect. The second equation can be used to find the minimum value of the excess noise factor for any multiplication when the dead space effect is completely dominant, the so called "deterministic" limit. This agrees with the theoretically known equation for multiplications less than or equal to two. © 2011 World Scientific Publishing Company.

Transforming growth factor β1 inhibition protects from noise-induced hearing loss

Directory of Open Access Journals (Sweden)

Silvia eMurillo-Cuesta

2015-03-01

Full Text Available Excessive exposure to noise damages the principal cochlear structures leading to hearing impairment. Inflammatory and immune responses are central mechanisms in cochlear defensive response to noise but, if unregulated, they contribute to inner ear damage and hearing loss. Transforming growth factor ß (TGF-ß is a key regulator of both responses and high levels of this factor have been associated with cochlear injury in hearing loss animal models. To evaluate the potential of targeting TGF-ß as a therapeutic strategy for preventing or ameliorating noise-induced hearing loss, we studied the auditory function, cochlear morphology, gene expression and oxidative stress markers in mice exposed to noise and treated with TGF-ß1 peptidic inhibitors P17 and P144, just before or immediately after noise insult. Our results indicate that systemic administration of both peptides significantly improved both the evolution of hearing thresholds and the degenerative changes induced by noise-exposure in lateral wall structures. Moreover, treatments ameliorated the inflammatory state and redox balance. These therapeutic effects were dose-dependent and more effective if the TGF-ß1 inhibitors were administered prior to inducing the injury. In conclusion, inhibition of TGF-ß1 actions with antagonistic peptides represents a new, promising therapeutic strategy for the prevention and repair of noise-induced cochlear damage.

A Fully Reconfigurable Low-Noise Biopotential Sensing Amplifier With 1.96 Noise Efficiency Factor.

Science.gov (United States)

Tzu-Yun Wang; Min-Rui Lai; Twigg, Christopher M; Sheng-Yu Peng

2014-06-01

A fully reconfigurable biopotential sensing amplifier utilizing floating-gate transistors is presented in this paper. By using the complementary differential pairs along with the current reuse technique, the theoretical limit for the noise efficiency factor of the proposed amplifier is below 1.5. Without consuming any extra power, floating-gate transistors are employed to program the low-frequency cutoff corner of the amplifier and to implement the common-mode feedback. A concept proving prototype chip was designed and fabricated in a 0.35 μm CMOS process occupying 0.17 mm (2) silicon area. With a supply voltage of 2.5 V, the measured midband gain is 40.7 dB and the measured input-referred noise is 2.8 μVrms. The chip was tested under several configurations with the amplifier bandwidth being programmed to 100 Hz, 1 kHz , and 10 kHz. The measured noise efficiency factors in these bandwidth settings are 1.96, 2.01, and 2.25, respectively, which are among the best numbers reported to date. The measured common-mode rejection and the supply rejection are above 70 dB . When the bandwidth is configured to be 10 kHz, the dynamic range measured at 1 kHz is 60 dB with total harmonic distortion less than 0.1%. The proposed amplifier is also demonstrated by recording electromyography (EMG), electrocardiography (ECG), electrooculography (EOG), and electroencephalography (EEG) signals from human bodies.

Effect of spatio-temporal noise in the Eddington factor on the scalar flux

International Nuclear Information System (INIS)

Prinja, Anil K.

2015-01-01

Highlights: • Spatio-temporal Gaussian noise is considered in the Eddington factor simulating noise in the low-order equation associated with a hybrid numerical solution technique for the transport equation. • A closed equation for the mean scalar flux is obtained that is accurate for small correlation times and exact in the white noise limit. • The equation for the mean scalar flux contains a fourth-order spatial derivative that is a consequence of the noise. • The fourth-order term is shown to destabilize all perturbations with wavelengths less than a critical value that depends on the noise amplitude, correlation length and time. • An asymptotic solution is shown to be possible for small noise amplitude. - Abstract: Spatial and temporal noise in the Eddington factor, simulating noise arising in hybrid numerical schemes, is modeled as a Gaussian stochastic process and its effect on the scalar flux investigated theoretically. In the small correlation time limit, a nonstandard closed equation for the mean scalar flux is obtained that contains a fourth order derivative of the scalar flux. In an infinite medium setting, this term is shown to have a destabilizing effect on the solution. Specifically, any spatial Fourier mode with wavelength smaller than a critical value, which depends on the noise characteristics, amplifies in time without bound, in contrast to the corresponding nonrandom case which is dissipative for all modes. An asymptotic solution is obtained which shows that the noise effect disappears at late times and the scalar flux limits to the deterministic solution.

Noise of screen-film systems: origins and components

Energy Technology Data Exchange (ETDEWEB)

Kuhn, H

1983-01-01

When using the more sensitive rare-earth intensifying screens in radiography applying the screen-film system, one has to cope with an increase in quantum noise. Measurement of Wiener spectra will help to determine the noise of the film. With an appropriate apparatus, the noise spectra of screen-film systems of different sensitivity have been ascertained and compared with theoretical assessments. The integral noise made up of the components film noise, screen noise and quantum noise have been thoroughly analysed. Adequate choice of radiographic conditions (such as modification of film exposure time via the screen, change of tube voltage) will affect the number of absorbed X-ray quanta in the luminous substance and thus the quantum noise which, as was found out, largely contributes to the integral noise together with another factor, graininess of the film. The study shows that although quantum noise has to be cut back, this should not be done at any price, and due regard must be paid to other factors influencing the image quality of the system, such as contrast and MTF.

Human response to wind turbine noise - perception, annoyance and moderating factors

Energy Technology Data Exchange (ETDEWEB)

Pedersen, Eja

2007-05-15

The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response. Methods A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. Subjective responses were obtained through a questionnaire (n = 513; response rate: 68%) and outdoor, A-weighted SPLs were calculated for each respondent. To gain a deeper understanding of the observed noise annoyance, 15 people living in an area were interviewed using open-ended questions. The interviews were analysed using the comparative method of Grounded Theory (GT). An additional cross-sectional study, mainly exploring the influence of individual and situational factors, was carried out in seven areas in Sweden that differed with regard to terrain (flat or complex) and degree of urbanization (n = 765; response rate: 58%). To further explore the impact of visual factors, data from the two cross-sectional studies were tested with structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see wind turbines versus respondents who could not see wind turbines from their dwelling, and respondents living in flat versus complex terrain. Dose-response relationships were found both for perception of noise and for noise annoyance in relation to A-weighted SPLs. The risk of annoyance was enhanced among respondents who could see at least one turbine from their dwelling and among those living in a rural in comparison with a suburban area. Noise from wind turbines was

Human response to wind turbine noise - perception, annoyance and moderating factors

International Nuclear Information System (INIS)

Pedersen, Eja

2007-05-01

The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response. Methods A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. Subjective responses were obtained through a questionnaire (n = 513; response rate: 68%) and outdoor, A-weighted SPLs were calculated for each respondent. To gain a deeper understanding of the observed noise annoyance, 15 people living in an area were interviewed using open-ended questions. The interviews were analysed using the comparative method of Grounded Theory (GT). An additional cross-sectional study, mainly exploring the influence of individual and situational factors, was carried out in seven areas in Sweden that differed with regard to terrain (flat or complex) and degree of urbanization (n = 765; response rate: 58%). To further explore the impact of visual factors, data from the two cross-sectional studies were tested with structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see wind turbines versus respondents who could not see wind turbines from their dwelling, and respondents living in flat versus complex terrain. Dose-response relationships were found both for perception of noise and for noise annoyance in relation to A-weighted SPLs. The risk of annoyance was enhanced among respondents who could see at least one turbine from their dwelling and among those living in a rural in comparison with a suburban area. Noise from wind turbines was

Making tensor factorizations robust to non-gaussian noise.

Energy Technology Data Exchange (ETDEWEB)

Chi, Eric C. (Rice University, Houston, TX); Kolda, Tamara Gibson

2011-03-01

Tensors are multi-way arrays, and the CANDECOMP/PARAFAC (CP) tensor factorization has found application in many different domains. The CP model is typically fit using a least squares objective function, which is a maximum likelihood estimate under the assumption of independent and identically distributed (i.i.d.) Gaussian noise. We demonstrate that this loss function can be highly sensitive to non-Gaussian noise. Therefore, we propose a loss function based on the 1-norm because it can accommodate both Gaussian and grossly non-Gaussian perturbations. We also present an alternating majorization-minimization (MM) algorithm for fitting a CP model using our proposed loss function (CPAL1) and compare its performance to the workhorse algorithm for fitting CP models, CP alternating least squares (CPALS).

Predictive factors of occupational noise-induced hearing loss in Spanish workers: A prospective study.

Science.gov (United States)

Pelegrin, Armando Carballo; Canuet, Leonides; Rodríguez, Ángeles Arias; Morales, Maria Pilar Arévalo

2015-01-01

The purpose of our study was to identify the main factors associated with objective noise-induced hearing loss (NIHL), as indicated by abnormal audiometric testing, in Spanish workers exposed to occupational noise in the construction industry. We carried out a prospective study in Tenerife, Spain, using 150 employees exposed to occupational noise and 150 age-matched controls who were not working in noisy environments. The variables analyzed included sociodemographic data, noise-related factors, types of hearing protection, self-report hearing loss, and auditory-related symptoms (e.g., tinnitus, vertigo). Workers with pathological audiograms had significantly longer noise-exposure duration (16.2 ± 11.4 years) relative to those with normal audiograms (10.2 ± 7.0 years; t = 3.99, P hearing protection measures had audiometric abnormalities (94.1%). Additionally, workers using at least one of the protection devices (earplugs or earmuffs) had significantly more audiometric abnormalities than those using both protection measures simultaneously (Chi square = 16.07; P hearing protection measures [odds ratio (OR) = 12.30, confidence interval (CI) = 4.36-13.81, P hearing protection measures, in particular earplugs and earmuffs, associates with a lower rate of audiometric abnormalities in subjects with high occupational noise exposure. The use of hearing protection measures at work and noise-exposure duration are best predictive factors of NIHL. Auditory-related symptoms and self-report hearing loss do not represent good indicators of objective NIHL. Routine monitoring of noise levels and hearing status are of great importance as part of effective hearing conservation programs.

Effect of drain current on appearance probability and amplitude of random telegraph noise in low-noise CMOS image sensors

Science.gov (United States)

Ichino, Shinya; Mawaki, Takezo; Teramoto, Akinobu; Kuroda, Rihito; Park, Hyeonwoo; Wakashima, Shunichi; Goto, Tetsuya; Suwa, Tomoyuki; Sugawa, Shigetoshi

2018-04-01

Random telegraph noise (RTN), which occurs in in-pixel source follower (SF) transistors, has become one of the most critical problems in high-sensitivity CMOS image sensors (CIS) because it is a limiting factor of dark random noise. In this paper, the behaviors of RTN toward changes in SF drain current conditions were analyzed using a low-noise array test circuit measurement system with a floor noise of 35 µV rms. In addition to statistical analysis by measuring a large number of transistors (18048 transistors), we also analyzed the behaviors of RTN parameters such as amplitude and time constants in the individual transistors. It is demonstrated that the appearance probability of RTN becomes small under a small drain current condition, although large-amplitude RTN tends to appear in a very small number of cells.

The temporal resolution factor with and without background noise

NARCIS (Netherlands)

Dreschler, W. A.; Leeuw, A. R.

1990-01-01

In this paper we discuss the measurement of the temporal resolution factor (TRF). The major merits of this measurement are that it is simple enough to be used clinically and that the results are, within certain limits, independent of presentation level. Addition of a continuous background noise has

Noise abatement technique for large vehicles of bus and truck families; Basu / torakku kei ogata sharyo no tei soon ka gijutsu

Energy Technology Data Exchange (ETDEWEB)

Takatsuki, K. [Isuzu Motors Ltd., Tokyo (Japan)

1997-09-25

It is remarked that noises in the cab of large buses and large trucks have been reduced about 10dB(A) during last 15 years, and experimental analytical methods for the noise abatement in the cab of these vehicles are introduced together with cases where measures are incorporated. Firstly, contribution to noise by each noise source is explained and a test method of noise exposure by the partial division of a large truck cab is presented, and on the base of the result obtained, it is found that the measures against the engin noise taken in cooperation with car manufacturer reside on the selection of noise absorbing/isolating materials and the actual examples are shown for a truck floor and the upper noise-proof structure of a bus. There are peaks at 100, 250 and 400 Hz on the noise spectra of an admission port, and they correspond to the problematic frequencies. Their analytical methods are presented comprising a speaker test, a simulation analysis and a boundary element method together with models and calculation examples. As for measures against the noise and vibration in the admission system, installation of resonator and vibration isolation by rubber are mentioned. Lastly, a synopsis on noise phenomena of the driving system is established and a twist resonance phenomenon that frequently occurs in the driving system is particularly described including their examples of analysis and countermeasures. 3 refs., 22 figs., 1 tab.

Calculation of the neutron noise induced by periodic deformations of a large sodium-cooled fast reactor core

International Nuclear Information System (INIS)

Zylbersztejn, F.; Tran, H.N.; Pazsit, I.; Filliatre, P.; Jammes, C.

2014-01-01

The subject of this paper is the calculation of the neutron noise induced by small-amplitude stationary radial variations of the core size (core expansion/compaction, also called core flowering) of a large sodium-cooled fast reactor. The calculations were performed on a realistic model of the European Sodium Fast Reactor (ESFR) core with a thermal output of 3600 MW(thermal), using a multigroup neutron noise simulator. The multigroup cross sections and their fluctuations that represent the core geometry changes for the neutron noise calculations were generated by the code ERANOS. The space and energy dependences of the noise source represented by the core expansion/compaction and the induced neutron noise are calculated and discussed. (authors)

Self-reported noise exposure as a risk factor for long-term sickness absence

DEFF Research Database (Denmark)

Clausen, Thomas; Christensen, Karl Bang; Lund, Thomas

2009-01-01

men and women when adjusting for demographic factors and health behavior. After further adjustment for physical workload at work the association between noise exposure and sickness absence disappeared for women, but not for men. Men that reported to be exposed to loud noise between one......Self-reported noise exposure is on the rise in Denmark. Little is known, however, about the social consequences, including sickness absence, of noise exposure. The aim of this paper was to investigate the association between self-reported noise exposure and long-term sickness absence....... The association was investigated using the Cox proportional hazards model to analyze outcomes in Danish register data on the basis of Danish survey data (5357 employees aged 18-69 in 2000). The analyses showed that self-reported noise exposure was significantly associated with long-term sickness absence for both...

Noise factor of a high-speed cinematography system

International Nuclear Information System (INIS)

Secroun, A.

2000-01-01

Inertial confinement fusion simulates in a laboratory the thermodynamic state of the center of stars, thus leading to the determination of stellar parameters. In order to reach that aim, high-speed cinematography brings up instruments specifically adapted to picosecond measurement, for which it is necessary to know the final precision. A model of the noise factor of the instruments under study is introduced and confronted to the experimental results obtained. (authors)

Ambient noise forecasting with a large acoustic array in a complex shallow water environment.

Science.gov (United States)

Rogers, Jeffrey S; Wales, Stephen C; Means, Steven L

2017-11-01

Forecasting ambient noise levels in the ocean can be a useful way of characterizing the detection performance of sonar systems and projecting bounds on performance into the near future. The assertion is that noise forecasting can be improved with a priori knowledge of source positions coupled with the ability to resolve closely separated sources in bearing. One example of such a system is the large aperture research array located at the South Florida Test Facility. Given radar and Automatic Identification System defined source positions and environmental information, transmission loss (TL) is computed from known source positions to the array. Source levels (SLs) of individual ships are then estimated from computed TL and the pre-determined beam response of the array using a non-negative least squares algorithm. Ambient noise forecasts are formed by projecting the estimated SLs along known ship tracks. Ambient noise forecast estimates are compared to measured beam level data and mean-squared error is computed. A mean squared error as low as 3.5 dB is demonstrated in 30 min forecast estimates when compared to ground truth.

Factors affecting the performance of large-aperture microphone arrays

Science.gov (United States)

Silverman, Harvey F.; Patterson, William R.; Sachar, Joshua

2002-05-01

Large arrays of microphones have been proposed and studied as a possible means of acquiring data in offices, conference rooms, and auditoria without requiring close-talking microphones. When such an array essentially surrounds all possible sources, it is said to have a large aperture. Large-aperture arrays have attractive properties of spatial resolution and signal-to-noise enhancement. This paper presents a careful comparison of theoretical and measured performance for an array of 256 microphones using simple delay-and-sum beamforming. This is the largest currently functional, all digital-signal-processing array that we know of. The array is wall-mounted in the moderately adverse environment of a general-purpose laboratory (8 m×8 m×3 m). The room has a T60 reverberation time of 550 ms. Reverberation effects in this room severely impact the array's performance. However, the width of the main lobe remains comparable to that of a simplified prediction. Broadband spatial resolution shows a single central peak with 10 dB gain about 0.4 m in diameter at the -3 dB level. Away from that peak, the response is approximately flat over most of the room. Optimal weighting for signal-to-noise enhancement degrades the spatial resolution minimally. Experimentally, we verify that signal-to-noise gain is less than proportional to the square root of the number of microphones probably due to the partial correlation of the noise between channels, to variation of signal intensity with polar angle about the source, and to imperfect correlation of the signal over the array caused by reverberations. We show measurements of the relative importance of each effect in our environment.

Background Noise Acceptance and Personality Factors Involved in Library Environment Choices by College Students

Science.gov (United States)

Gordon-Hickey, Susan; Lemley, Trey

2012-01-01

For decades, academic libraries made efforts to provide study environments differing in acoustic environment. The present study aimed to provide an evidence basis for this practice by comparing background noise acceptance and personality factors of two groups of college-aged students self identified as preferring quiet or background noise when…

Recent advances in research on non-auditory effects of community noise

Directory of Open Access Journals (Sweden)

Belojević Goran

2016-01-01

Full Text Available Non-auditory effects of noise on humans have been intensively studied in the last four decades. The International Commission on Biological Effects of Noise has been following scientific advances in this field by organizing international congresses from the first one in 1968 in Washington, DC, to the 11th congress in Nara, Japan, in 2014. There is already a large scientific body of evidence on the effects of noise on annoyance, communication, performance and behavior, mental health, sleep, and cardiovascular functions including relationship with hypertension and ischemic heart disease. In the last five years new issues in this field have been tackled. Large epidemiological studies on community noise have reported its relationship with breast cancer, stroke, type 2 diabetes, and obesity. It seems that noise-induced sleep disturbance may be one of the mediating factors in these effects. Given a large public health importance of the above-mentioned diseases, future studies should more thoroughly address the mechanisms underlying the reported association with community noise exposure. [Projekat Ministarstva nauke Republike Srbije, br. 175078

Shear wave velocity versus quality factor: results from seismic noise recordings

Science.gov (United States)

Boxberger, Tobias; Pilz, Marco; Parolai, Stefano

2017-08-01

The assessment of the shear wave velocity (vs) and shear wave quality factor (Qs) for the shallow structure below a site is necessary to characterize its site response. In the past, methods based on the analysis of seismic noise have been shown to be very efficient for providing a sufficiently accurate estimation of the vs versus depth at reasonable costs for engineering seismology purposes. In addition, a slight modification of the same method has proved to be able to provide realistic Qs versus depth estimates. In this study, data sets of seismic noise recorded by microarrays of seismic stations in different geological environments of Europe and Central Asia are used to calculate both vs and Qs versus depth profiles. Analogous to the generally adopted approach in seismic hazard assessment for mapping the average shear wave velocity in the uppermost 30 m (vs30) as a proxy of the site response, this approach was also applied to the quality factor within the uppermost 30 m (Qs30). A slightly inverse correlation between both parameters is found based on a methodological consistent determination for different sites. Consequently, a combined assessment of vs and Qs by seismic noise analysis has the potential to provide a more comprehensive description of the geological structure below a site.

Auditory and Cognitive Factors Associated with Speech-in-Noise Complaints following Mild Traumatic Brain Injury.

Science.gov (United States)

Hoover, Eric C; Souza, Pamela E; Gallun, Frederick J

2017-04-01

Auditory complaints following mild traumatic brain injury (MTBI) are common, but few studies have addressed the role of auditory temporal processing in speech recognition complaints. In this study, deficits understanding speech in a background of speech noise following MTBI were evaluated with the goal of comparing the relative contributions of auditory and nonauditory factors. A matched-groups design was used in which a group of listeners with a history of MTBI were compared to a group matched in age and pure-tone thresholds, as well as a control group of young listeners with normal hearing (YNH). Of the 33 listeners who participated in the study, 13 were included in the MTBI group (mean age = 46.7 yr), 11 in the Matched group (mean age = 49 yr), and 9 in the YNH group (mean age = 20.8 yr). Speech-in-noise deficits were evaluated using subjective measures as well as monaural word (Words-in-Noise test) and sentence (Quick Speech-in-Noise test) tasks, and a binaural spatial release task. Performance on these measures was compared to psychophysical tasks that evaluate monaural and binaural temporal fine-structure tasks and spectral resolution. Cognitive measures of attention, processing speed, and working memory were evaluated as possible causes of differences between MTBI and Matched groups that might contribute to speech-in-noise perception deficits. A high proportion of listeners in the MTBI group reported difficulty understanding speech in noise (84%) compared to the Matched group (9.1%), and listeners who reported difficulty were more likely to have abnormal results on objective measures of speech in noise. No significant group differences were found between the MTBI and Matched listeners on any of the measures reported, but the number of abnormal tests differed across groups. Regression analysis revealed that a combination of auditory and auditory processing factors contributed to monaural speech-in-noise scores, but the benefit of spatial separation was

Combined factors effect of menstrual cycle and background noise on visual inspection task performance: a simulation-based task.

Science.gov (United States)

Wijayanto, Titis; Tochihara, Yutaka; Wijaya, Andi R; Hermawati, Setia

2009-11-01

It is well known that women are physiologically and psychologically influenced by the menstrual cycle. In addition, the presence of background noise may affect task performance. So far, it has proven difficult to describe how the menstrual cycle and background noise affect task performance; some researchers have found an increment of performance during menstruation or during the presence of noise, others found performance deterioration, while other still have reported no dominant effect either of the menstrual cycle in performance or of the presence of noise. However, no study to date has investigated the combinational effect between the menstrual cycle and the presence of background noise in task performance. Therefore, the purpose of this study was to examine the combined factor effect of menstrual cycle and background noise on visual inspection task performance indices by Signal Detection Theory (SDT) metrics: sensitivity index (d') and response criteria index (beta). For this purpose, ten healthy female students (21.5+/-1.08 years) with a regular menstrual cycle participated in this study. A VDT-based visual inspection task was used for the experiment in 3x2 factorial designs. Two factors, menstrual phase, pre-menstruation (PMS), menstruation (M), and post-menstruation (PM) and background noise, with 80 dB(A) background noise and without noise, were analyzed as the main factors in this study. The results concluded that the sensitivity index (d') of SDT was affected in all the menstrual cycle conditions (pbackground noise (pbackground noise was found in this study. On the other hand, no significant effect was observed in the subject's tendency in visual inspection, shown by beta along the menstrual cycle and the presence of background noise. According to the response criteria for each individual subject, the presence of noise affected the tendency of some subjects in detecting the object and making decision during the visual inspection task.

Shot noise and Fano factor in tunneling in three-band pseudospin-1 Dirac-Weyl systems

Science.gov (United States)

Zhu, Rui; Hui, Pak Ming

2017-06-01

Tunneling through a potential barrier of height V0 in a two-dimensional system with a band structure consisting of three bands with a flat band intersecting the touching apices of two Dirac cones is studied. Results of the transmission coefficient at various incident angles, conductivity, shot noise, and Fano factor in this pseudospin-1 Dirac-Weyl system are presented and contrasted with those in graphene which is typical of a pseudospin-1/2 system. The pseudospin-1 system is found to show a higher transmission and suppressed shot noise in general. Significant differences in the shot noise and Fano factor due to the super Klein tunneling effect that allows perfect transmission at all incident angles under certain conditions are illustrated. For Fermi energy EF =V0 / 2, super Klein tunneling leads to a noiseless conductivity that takes on the maximum value 2e2 DkF / (πh) for 0 ≤EF ≤V0. This gives rise to a minimum Fano factor, in sharp contrast with that of a local maximum in graphene. For EF =V0, the band structure of pseudospin-1 system no longer leads to a quantized value of the conductivity as in graphene. Both the conductivity and the shot noise show a minimum with the Fano factor approaching 1/4, which is different from the value of 1/3 in graphene.

High-fidelity large eddy simulation for supersonic jet noise prediction

Science.gov (United States)

Aikens, Kurt M.

The problem of intense sound radiation from supersonic jets is a concern for both civil and military applications. As a result, many experimental and computational efforts are focused at evaluating possible noise suppression techniques. Large-eddy simulation (LES) is utilized in many computational studies to simulate the turbulent jet flowfield. Integral methods such as the Ffowcs Williams-Hawkings (FWH) method are then used for propagation of the sound waves to the farfield. Improving the accuracy of this two-step methodology and evaluating beveled converging-diverging nozzles for noise suppression are the main tasks of this work. First, a series of numerical experiments are undertaken to ensure adequate numerical accuracy of the FWH methodology. This includes an analysis of different treatments for the downstream integration surface: with or without including an end-cap, averaging over multiple end-caps, and including an approximate surface integral correction term. Secondly, shock-capturing methods based on characteristic filtering and adaptive spatial filtering are used to extend a highly-parallelizable multiblock subsonic LES code to enable simulations of supersonic jets. The code is based on high-order numerical methods for accurate prediction of the acoustic sources and propagation of the sound waves. Furthermore, this new code is more efficient than the legacy version, allows cylindrical multiblock topologies, and is capable of simulating nozzles with resolved turbulent boundary layers when coupled with an approximate turbulent inflow boundary condition. Even though such wall-resolved simulations are more physically accurate, their expense is often prohibitive. To make simulations more economical, a wall model is developed and implemented. The wall modeling methodology is validated for turbulent quasi-incompressible and compressible zero pressure gradient flat plate boundary layers, and for subsonic and supersonic jets. The supersonic code additions and the

Noise sensitivity and reactions to noise and other environmental conditions

NARCIS (Netherlands)

Miedema, H.M.E.; Vos, H.

2003-01-01

This article integrates findings from the literature and new results regarding noise sensitivity. The new results are based on analyses of 28 combined datasets (N=23 038), and separate analyses of a large aircraft noise study (N=10939). Three topics regarding noise sensitivity are discussed, namely,

Overview of en route noise prediction using a integrated noise model

Science.gov (United States)

2010-04-20

En route aircraft noise is often ignored in aircraft noise modeling because large amounts of noise attenuation due to long propagation distances between the aircraft and the receivers on the ground, reduced power in cruise flight compared to takeoff ...

[Current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry].

Science.gov (United States)

Wu, S S; Yu, J N; He, C H; Mu, H X; Wang, C; Zhang, Y; Zhang, C Y; Yu, S F; Li, X L

2016-12-20

Objective: To investigate the current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry. Methods: From August 2015 to March 2016, the investigation method of collecting the data of past occupational health examinations and measuring noise in working environment was used to enroll 8 672 male workers. Results: Of all workers, 11.6% were diagnosed with hearing loss. There were significant differences in the distribution of hearing impairment among workers exposed to noise at different ages, device types and types of work (χ(2)=17.80, 77.80 and 30.53, all P hearing loss in workers with noise exposure in refining and chemical industry. Conclusion: The level of noise exposure and working years with noise exposure are main influencing factors for hearing loss in workers with noise exposure in refining and chemical industry.

[Influencing factors for hearing loss in workers exposed to noise in a cement plant].

Science.gov (United States)

Wang, X M; Wu, H; Jiao, J; Li, Y H; Zhang, Z R; Zhou, W H; Yu, S F

2016-12-20

Objective: To investigate the incidence of noise-induced hearing loss (NIHL) and related influencing factors in workers exposed to noise in a cement plant. Methods: In October 2015, cluster sampling was used for questionnaire investigation and health examination of workers exposed to noise in a cement plant in Henan Province, China. The association of demographic features, living habits, cumulative noise exposure (CNE) , hypertension, and hyperlipidemia with NIHL was analyzed. Results: There was mainly medium-or high-frequency noise in the working place of this cement plant. The prevalence rate of NIHL was 18.4%, and male workers had a significantly higher prevalence rate than female workers (χ(2)=28.09, P workers who smoked had a significantly higher prevalence rate of NIHL than those who did not smoke (χ(2)=14.15, P workers with a drinking habit had a significantly higher prevalence rate of NIHL than those without such habit (χ(2)=7.95, P workers who did not wear earplugs had a significantly higher prevalence rate of NIHL than those who wore earplugs (χ(2)=19.93, P workers with hyperlipidemiahad a significantly higher prevalence rate of NIHL than those without hyperlipidemia (χ(2)=12.43, P workers in a cement plant have a high prevalence rate of NIHL, and CNE, sex, age, degree of education, use of earplugs, and hyperlipidemia may be influencing factors for NIHL.

Interior Noise Predictions in the Preliminary Design of the Large Civil Tiltrotor (LCTR2)

Science.gov (United States)

Grosveld, Ferdinand W.; Cabell, Randolph H.; Boyd, David D.

2013-01-01

A prediction scheme was established to compute sound pressure levels in the interior of a simplified cabin model of the second generation Large Civil Tiltrotor (LCTR2) during cruise conditions, while being excited by turbulent boundary layer flow over the fuselage, or by tiltrotor blade loading and thickness noise. Finite element models of the cabin structure, interior acoustic space, and acoustically absorbent (poro-elastic) materials in the fuselage were generated and combined into a coupled structural-acoustic model. Fluctuating power spectral densities were computed according to the Efimtsov turbulent boundary layer excitation model. Noise associated with the tiltrotor blades was predicted in the time domain as fluctuating surface pressures and converted to power spectral densities at the fuselage skin finite element nodes. A hybrid finite element (FE) approach was used to compute the low frequency acoustic cabin response over the frequency range 6-141 Hz with a 1 Hz bandwidth, and the Statistical Energy Analysis (SEA) approach was used to predict the interior noise for the 125-8000 Hz one-third octave bands.

Noise and Spurious Tones Management Techniques for Multi-GHz RF-CMOS Frequency Synthesizers Operating in Large Mixed Analog-Digital SOCs

Directory of Open Access Journals (Sweden)

Maxim Adrian

2006-01-01

Full Text Available This paper presents circuit techniques and power supply partitioning, filtering, and regulation methods aimed at reducing the phase noise and spurious tones in frequency synthesizers operating in large mixed analog-digital system-on-chip (SOC. The different noise and spur coupling mechanisms are presented together with solutions to minimize their impact on the overall PLL phase noise performance. Challenges specific to deep-submicron CMOS integration of multi-GHz PLLs are revealed, while new architectures that address these issues are presented. Layout techniques that help reducing the parasitic noise and spur coupling between digital and analog blocks are described. Combining system-level and circuit-level low noise design methods, low phase noise frequency synthesizers were achieved which are compatible with the demanding nowadays wireless communication standards.

Comprehensive quantification of signal-to-noise ratio and g-factor for image-based and k-space-based parallel imaging reconstructions.

Science.gov (United States)

Robson, Philip M; Grant, Aaron K; Madhuranthakam, Ananth J; Lattanzi, Riccardo; Sodickson, Daniel K; McKenzie, Charles A

2008-10-01

Parallel imaging reconstructions result in spatially varying noise amplification characterized by the g-factor, precluding conventional measurements of noise from the final image. A simple Monte Carlo based method is proposed for all linear image reconstruction algorithms, which allows measurement of signal-to-noise ratio and g-factor and is demonstrated for SENSE and GRAPPA reconstructions for accelerated acquisitions that have not previously been amenable to such assessment. Only a simple "prescan" measurement of noise amplitude and correlation in the phased-array receiver, and a single accelerated image acquisition are required, allowing robust assessment of signal-to-noise ratio and g-factor. The "pseudo multiple replica" method has been rigorously validated in phantoms and in vivo, showing excellent agreement with true multiple replica and analytical methods. This method is universally applicable to the parallel imaging reconstruction techniques used in clinical applications and will allow pixel-by-pixel image noise measurements for all parallel imaging strategies, allowing quantitative comparison between arbitrary k-space trajectories, image reconstruction, or noise conditioning techniques. (c) 2008 Wiley-Liss, Inc.

[Influencing factors for the use of earplugs in workers exposed to noise in a city].

Science.gov (United States)

Zhu, Q R; Shao, Y X; Cao, C J; Wu, X; Xie, W Q; Xu, M; Yang, L; Xu, L W

2016-04-20

To investigate the current status of hearing loss and the use of earplugs in workers exposed to noise who have been provided earplugs in a city, as well as major influencing factors for the use of earplugs. Cluster random sampling was used to conduct a questionnaire survey in workers exposed to noise who had been provided earplugs in 15 enterprises with noise exposure in a city from June to December, 2014. In the workers exposed to noise who had been provided earplugs, the rate of high-frequency anomaly in both ears was 57.8%, and the workers who kept wearing earplugs only accounted for 55.4%. The results of binary logistic regression analysis showed that the protective factors for the use of earplugs included workers' own feeling of hearing condition (OR=1.704), comfort of earplugs (OR= 1.892), enterprise's inspection of the use of earplugs (OR=1.461), workers' knowledge of the function and usage of earplugs (OR=1.581), workers' understanding of the necessity of earplugs (OR=4.482), workers' initiative to search for related data (OR=4.029), the use of earplugs by colleagues (OR=5.071), and reminders from family members or friends (OR=2.678) (all Pworkers exposed to noise in this city have a high rate of abnormal hearing, and only half of the workers keep wearing earplugs during work. The use of earplugs is related to the factors including workers' own feeling of hearing condition, comfort of earplugs, workers' knowledge of protection, the enterprise' s management of hearing protection, and environmental support.

High internal noise and poor external noise filtering characterize perception in autism spectrum disorder.

Science.gov (United States)

Park, Woon Ju; Schauder, Kimberly B; Zhang, Ruyuan; Bennetto, Loisa; Tadin, Duje

2017-12-14

An emerging hypothesis postulates that internal noise is a key factor influencing perceptual abilities in autism spectrum disorder (ASD). Given fundamental and inescapable effects of noise on nearly all aspects of neural processing, this could be a critical abnormality with broad implications for perception, behavior, and cognition. However, this proposal has been challenged by both theoretical and empirical studies. A crucial question is whether and how internal noise limits perception in ASD, independently from other sources of perceptual inefficiency, such as the ability to filter out external noise. Here, we separately estimated internal noise and external noise filtering in ASD. In children and adolescents with and without ASD, we computationally modeled individuals' visual orientation discrimination in the presence of varying levels of external noise. The results revealed increased internal noise and worse external noise filtering in individuals with ASD. For both factors, we also observed high inter-individual variability in ASD, with only the internal noise estimates significantly correlating with severity of ASD symptoms. We provide evidence for reduced perceptual efficiency in ASD that is due to both increased internal noise and worse external noise filtering, while highlighting internal noise as a possible contributing factor to variability in ASD symptoms.

Practical Ranges of Loudness Levels of Various Types of Environmental Noise, Including Traffic Noise, Aircraft Noise, and Industrial Noise

Directory of Open Access Journals (Sweden)

Sabine A. Janssen

2011-05-01

Full Text Available In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A‑weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels.

Increase of Investment Appeal of Projects for Noise Control Measures in Urban Environment

Science.gov (United States)

Kolmakov, A. V.; Ignatyeva, V. O.

2017-11-01

The authors analyzed the contemporary noise pollution level in the large cities of the Russian Federation. The article identifies the factors causing the reduction of acoustically comfortable urban territories. It states the task for the increase of investment appeal of the projects aimed at noise control measures adoption.

Prediction of broadband trailing edge noise from a NACA0012 airfoil using wall-modeled large-eddy simulation

Science.gov (United States)

Mehrabadi, Mohammad; Bodony, Daniel

2017-11-01

In modern high-bypass ratio turbofan engines, the reduction of jet exhaust noise through engine design has increased the acoustic importance of the main fan to the point where it can be the primary source of noise in the fight direction of an airplane. While fan noise has been reduced by improved fan designs, its broadband component, originating from the interaction of turbulent flow with a solid surface, still remains an issue. Broadband fan noise is generated by several mechanisms, usually involving a turbulent boundary layer interacting with a solid surface. To prepare for a wall modeled large eddy simulation (WMLES) of the NASA/GE source diagnostic test fan, we study the broadband noise due to the turbulent flow on a NACA0012 airfoil at zero degree angle-of-attack, a chord-based Reynolds number of 408,000, and a Mach number of 0.115 using WMLES. We investigate the prediction of transition-to-turbulence and sound generation from the WMLES and examine its predictability compared with available experimental and DNS datasets for the same flow conditions. Verification of WMLES for such a canonical problem is crucial since it provides useful insight about the WMLES approach before using it for broadband fan noise prediction. AeroAcoustics Research Consortium.

Noise-intolerance and state-dependent factors in patients with whiplash associated disorder

NARCIS (Netherlands)

Blokhorst, M.G.B.G.; Meeldijk, S.J.; Luijtelaar, E.L.J.M. van; Toor, T. van; Lousberg, R.; Ganzevles, P.

2005-01-01

An experiment was carried out in which the level of noise-intolerance in patients with a Whiplash Associated Disorder (WAD) was compared to healthy matched control subjects. In addition, the relationship between state-dependent factors (as headache, neck pain, fatigue and tension) and

The noise factor in railway locomotives.

Science.gov (United States)

Rotter, T

1982-09-01

This article concerns the problem of acoustic work conditions on railway locomotives. The objective results of sonometric surveys in locomotive cabins are compared with subject data received from locomotive crews obtained by means of a specific questionnaire 'The Subjective Estimation of Noise'. The analysis touched 9 type of locomotives; steam, diesel and electric engines. We asked drivers of different age groups and with varying lengths of professional service for their opinions The aim of the investigation was to determine the following points: 1. to analyse the drivers' subjective estimation of the noise in the locomotive cabins; 2. to define length of time for which the driver remains under the influence of the noise after finishing work; 3. to investigate the question of perception and understanding of sounds and vocal signals used in the locomotive. These problems are a small part of the general plan to improve work conditions on the Polish National Railways.

An analysis of low frequency noise from large wind turbines

DEFF Research Database (Denmark)

Pedersen, Christian Sejer; Møller, Henrik

2010-01-01

As wind turbines get larger, worries have emerged, that the noise emitted by the turbines would move down in frequency, and that the contents of low-frequency noise would be enough to cause significant annoyance for the neighbors. The sound emission from 48 wind turbines with nominal electric power......-third-octave-band spectra shows that the relative noise emission is higher in the 63-250 Hz frequency range from turbines above 2 MW than from smaller turbines. The observations confirm a downward shift of the spectrum....

MOSFET LF noise under Large Signal Excitation: Measurement, Modelling and Application

NARCIS (Netherlands)

van der Wel, A.P.

2005-01-01

Regarding LF noise in MOSFETs, it is noted that the MOSFET is a surface channel device. Both n and p-channel devices exhibit similar low frequency (LF) noise behaviour that can be explained by a carrier number fluctuation model (section 3.5). LF noise in MOSFETs is predominantly caused by Random

[Investigation of occupational noise exposure and hearing loss in large automobile manufacturing enterprise during 2006-2010 in Guangzhou, China].

Science.gov (United States)

Zhao, Yuan; Zhou, Hao; Li, Yanhua; Xiao, Lvwu; Wu, Lin; Du, Weijia; Liu, Yimin

2014-02-01

To analyze the relationship between occupational noise exposure and hearing loss among workers in large automobile manufacturing enterprise during 2006-2010 in Guangzhou, China. A retrospective cohort study was conducted. The subjects were divided into noise exposure group and control group. Their hearing examination results and noise exposure levels in different workplaces were collected during 2006-2010, and the relationship between noise exposure in workplaces and hearing loss was analyzed. The incidence of hearing loss for the noise exposure group was 9.34%, versus 2.75% for the control group; the noise exposure group had a significantly higher risk of hearing loss than the control group (R = 3.378, 95%CI = 1.467∼ 9.083). The noise intensity and over-limit rate were significantly higher in the stamping, welding, and general assembly workshops than in other workshops. The risk of hearing loss significantly increased with years of noise exposure in 80, 85, and 90 dB (A) groups (χ(2) = 6.377, P = 0.041; χ(2) = 8.570, P = 0.014; χ(2) = 7.037, P = 0.030). The risk of hearing loss also increased with noise intensity in all working age groups (χ(2) = 5.068, P = 0.024; χ(2) = 71.497, P hearing loss in workers. The incidence of hearing loss increases with the noise intensity in workplaces and years of noise exposure. The noise exposure level and incidence of hearing loss are higher in the stamping workshop than in other workshops. Controlling the noise intensity in automobile manufacturing enterprise may reduce the risk of hearing loss in workers.

State-of-the-Art Review on Sustainable Design and Construction of Quieter Pavements—Part 2: Factors Affecting Tire-Pavement Noise and Prediction Models

Directory of Open Access Journals (Sweden)

Okan Sirin

2016-07-01

Full Text Available Traffic noise is a combination of noises produced from a number of sources. Of all the traffic noise sources, tire-pavement noise, which is emitted as a result of the interaction of rolling, slipping, or dragging tires and the pavement surface, is the dominant contributor of overall noise, particularly when vehicles are moving at higher speeds. Therefore, a number of research studies have been conducted to identify and analyze the factors affecting the generation of tire-pavement interaction noise. This helps in identifying and selecting appropriate noise mitigation techniques. In this paper, an extensive literature survey on the factors affecting tire-pavement noise is presented, and different views on the impact of each individual factor are discussed. From the literature survey, it is also evident that there is a potential correlation between pavement’s material characteristics and tire-pavement noise. A comprehensive discussion about this correlation is presented in the paper. In addition, this paper discusses various mathematical models for predicting pavement noise, and their advantages and shortcomings.

Demographic and attitudinal factors that modify annoyance from transportation noise

NARCIS (Netherlands)

Miedema, H.M.E.; Vos, H.

1999-01-01

The effect of demographic variables (sex, age, education level, occupational status, size of household, homeownership, dependency on the noise source, and use of the noise source) and two attitudinal variables (noise sensitivity and fear of the noise source) on noise annoyance is investigated. It is

The solar noise barrier project : 2. The effect of street art on performance of a large scale luminescent solar concentrator prototype

NARCIS (Netherlands)

Debije, M.G.; Tzikas, C.; Rajkumar, V.A.; de Jong, M.

2017-01-01

Noise barriers have been used worldwide to reduce the impact of sound generated from traffic on nearby areas. A common feature to appear on these noise barriers are all manner of graffiti and street art. In this work we describe the relative performance of a large area luminescent solar concentrator

Development of Active Noise Control System for Quieting Transformer Noise

Energy Technology Data Exchange (ETDEWEB)

Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

1997-12-31

The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

Low voltage excess noise and shot noise in YBCO bicrystal junctions

DEFF Research Database (Denmark)

Constantinian, K.Y.; Ovsyannikov, G.A.; Borisenko, I.V.

2002-01-01

The spectral density of background noise emitted by symmetric bicrystal YBaCuO Josephson junctions on sapphire substrates have been measured by a low noise cooled HEMT amplifier for bias voltages up to V approximate to 50 mV. At relatively low voltages V noise rise has been...... registered. At large bias voltages V > 30 mV a clear dependence of noise power. exactly coinciding to the asymptote of the Schottky shot noise function, has been observed for the first time. Experimental results are discussed in terms of multiple Andreev reflections which may take place in d...

Long-termexposure to road traffic noise, ambient air pollution, and cardiovascular risk factors in the HUNT and lifelines cohorts

NARCIS (Netherlands)

Cai, Yutong; Hansell, Anna L.; Blangiardo, Marta; Burton, Paul R.; de Hoogh, Kees; Doiron, Dany; Fortier, Isabel; Gulliver, John; Hveem, Kristian; Mbatchou, Stéphane; Morley, DavidW.; Stolk, Ronald P.; Zijlema, Wilma L.; Elliott, Paul; Hodgson, Susan

2017-01-01

Aims: Blood biochemistry may provide information on associations between road traffic noise, air pollution, and cardiovascular disease risk. We evaluated this in two large European cohorts (HUNT3, Lifelines). Methods and results: Road traffic noise exposure was modelled for 2009 using a simplified

Signal and noise analysis in TRION-Time-Resolved Integrative Optical Fast Neutron detector

International Nuclear Information System (INIS)

Vartsky, D; Feldman, G; Mor, I; Goldberg, M B; Bar, D; Dangendorf, V

2009-01-01

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event-counting detectors where the signal-to-noise ratio is dependent only on the number of detected events (quantum noise), in an energy-integrating detector additional factors, such as the fluctuations in imparted energy, number of photoelectrons, system gain and other factors will contribute to the noise. The excess noise factor (over the quantum noise) due to these processes was 4.3, 2.7, 2.1, 1.9 and 1.9 for incident neutron energies of 2, 4, 7.5, 10 and 14 MeV, respectively. It is shown that, even under ideal light collection conditions, a fast neutron detection system operating in an integrative mode cannot be quantum-noise-limited due to the relatively large variance in the imparted proton energy and the resulting scintillation light distributions.

Risk assessment of influence factors on occupational hearing loss in noise – exposed workers in typical metal industry

OpenAIRE

Farhadian Maryam; Aliabadi Mohsen; Shahidi Reza

2014-01-01

Background & Objectives : Worker exposure conditions such as noise level, exposure duration, use of hearing protection devices and health behaviors are commonly related to noise induced hearing loss. The objective of this study was risk assessment of influence factors on occupational hearing loss in noise exposed workers in typical noisy process . Methods : Information about occupational exposure of seventy workers employed in a noisy press workshop was gathered using the standard quest...

Noise and Fano-Factor Control in AC-Driven Aharonov-Casher Ring

Directory of Open Access Journals (Sweden)

Zein W. A.

2011-01-01

Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

Noise and Fano-factor Control in AC-Driven Aharonov-Casher Ring

Directory of Open Access Journals (Sweden)

Phillips A. H.

2011-01-01

Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

Road traffic noise: self-reported noise annoyance versus GIS modelled road traffic noise exposure.

Science.gov (United States)

Birk, Matthias; Ivina, Olga; von Klot, Stephanie; Babisch, Wolfgang; Heinrich, Joachim

2011-11-01

self-reported road traffic noise annoyance is commonly used in epidemiological studies for assessment of potential health effects. Alternatively, some studies have used geographic information system (GIS) modelled exposure to road traffic noise as an objective parameter. The aim of this study was to analyse the association between noise exposure due to neighbouring road traffic and the noise annoyance of adults, taking other determinants into consideration. parents of 951 Munich children from the two German birth cohorts GINIplus and LISAplus reported their annoyance due to road traffic noise at home. GIS modelled road traffic noise exposure (L(den), maximum within a 50 m buffer) from the noise map of the city of Munich was available for all families. GIS-based calculated distance to the closest major road (≥10,000 vehicles per day) and questionnaire based-information about family income, parental education and the type of the street of residence were explored for their potential influence. An ordered logit regression model was applied. The noise levels (L(den)) and the reported noise annoyance were compared with an established exposure-response function. the correlation between noise annoyance and noise exposure (L(den)) was fair (Spearman correlation r(s) = 0.37). The distance to a major road and the type of street were strong predictors for the noise annoyance. The annoyance modelled by the established exposure-response function and that estimated by the ordered logit model were moderately associated (Pearson's correlation r(p) = 0.50). road traffic noise annoyance was associated with GIS modelled neighbouring road traffic noise exposure (L(den)). The distance to a major road and the type of street were additional explanatory factors of the noise annoyance appraisal.

Newtonian-noise cancellation in large-scale interferometric GW detectors using seismic tiltmeters

International Nuclear Information System (INIS)

Harms, Jan; Venkateswara, Krishna

2016-01-01

The mitigation of terrestrial gravity noise, also known as Newtonian noise (NN), is one of the foremost challenges to improve low-frequency sensitivity of ground-based gravitational-wave detectors. At frequencies above 1 Hz, it is predicted that gravity noise from seismic surface Rayleigh waves is the dominant contribution to NN in surface detectors, and may still contribute significantly in future underground detectors. Noise cancellation based on a coherent estimate of NN using data from a seismometer array was proposed in the past. In this article, we propose an alternative scheme to cancel NN using a seismic tiltmeter. It is shown that even under pessimistic assumptions concerning the complexity of the seismic field, a single tiltmeter under each test mass of the detector is sufficient to achieve substantial noise cancellation. A technical tiltmeter design is presented to achieve the required sensitivity in the Newtonian-noise frequency band. (paper)

A Tunable Low Noise Active Bandpass Filter Using a Noise Canceling Technique

OpenAIRE

Soltani, N.

2016-01-01

A monolithic tunable low noise active bandpass filter is presented in this study. Biasing voltages can control the center frequency and quality factor. By keeping the gain constant, the center frequency shift is 300 MHz. The quality factor can range from 90 to 290 at the center frequency. By using a noise cancelling circuit, noise is kept lower than 2.8 dB. The proposed filter is designed using MMIC technology with a center frequency of 2.4 GHz and a power consumption of 180 mW. ED02AH techno...

Large Civil Tiltrotor (LCTR2) Interior Noise Predictions due to Turbulent Boundary Layer Excitation

Science.gov (United States)

Grosveld, Ferdinand W.

2013-01-01

The Large Civil Tiltrotor (LCTR2) is a conceptual vehicle that has a design goal to transport 90 passengers over a distance of 1800 km at a speed of 556 km/hr. In this study noise predictions were made in the notional LCTR2 cabin due to Cockburn/Robertson and Efimtsov turbulent boundary layer (TBL) excitation models. A narrowband hybrid Finite Element (FE) analysis was performed for the low frequencies (6-141 Hz) and a Statistical Energy Analysis (SEA) was conducted for the high frequency one-third octave bands (125- 8000 Hz). It is shown that the interior sound pressure level distribution in the low frequencies is governed by interactions between individual structural and acoustic modes. The spatially averaged predicted interior sound pressure levels for the low frequency hybrid FE and the high frequency SEA analyses, due to the Efimtsov turbulent boundary layer excitation, were within 1 dB in the common 125 Hz one-third octave band. The averaged interior noise levels for the LCTR2 cabin were predicted lower than the levels in a comparable Bombardier Q400 aircraft cabin during cruise flight due to the higher cruise altitude and lower Mach number of the LCTR2. LCTR2 cabin noise due to TBL excitation during cruise flight was found not unacceptable for crew or passengers when predictions were compared to an acoustic survey on a Q400 aircraft.

0069 Psychosocial work factors, occupational noise exposure, common mental disorders, and the risk of tinnitus

DEFF Research Database (Denmark)

Winther Frederiksen, Thomas; Ramlau-Hansen, Cecilia H; Stokholm, Zara A

2014-01-01

OBJECTIVES: Tinnitus is common, can be disabling, and may impair concentration, hearing and sleep. Noise induced hearing loss, other subtypes of hearing loss and ototoxic drugs are well-documented risk factors for tinnitus. Psychosocial work factors, depression and anxiety may exacerbate tinnitus...

Sex Differences in Susceptibility and Resistance to Noise-Induced Hearing Loss in Chinchillas

National Research Council Canada - National Science Library

McFadden, Sandra

1999-01-01

.... The reasons for individual differences in susceptibility to noise-induced hearing loss (NIHL) are largely unknown, but may include factors such as levels of endogenous antioxidant enzymes or steroid hormones...

Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

Science.gov (United States)

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

Definition of 1992 Technology Aircraft Noise Levels and the Methodology for Assessing Airplane Noise Impact of Component Noise Reduction Concepts

Science.gov (United States)

Kumasaka, Henry A.; Martinez, Michael M.; Weir, Donald S.

1996-01-01

This report describes the methodology for assessing the impact of component noise reduction on total airplane system noise. The methodology is intended to be applied to the results of individual study elements of the NASA-Advanced Subsonic Technology (AST) Noise Reduction Program, which will address the development of noise reduction concepts for specific components. Program progress will be assessed in terms of noise reduction achieved, relative to baseline levels representative of 1992 technology airplane/engine design and performance. In this report, the 1992 technology reference levels are defined for assessment models based on four airplane sizes - an average business jet and three commercial transports: a small twin, a medium sized twin, and a large quad. Study results indicate that component changes defined as program final goals for nacelle treatment and engine/airframe source noise reduction would achieve from 6-7 EPNdB reduction of total airplane noise at FAR 36 Stage 3 noise certification conditions for all of the airplane noise assessment models.

The influence of acoustical and non-acoustical factors on short-term annoyance due to aircraft noise in the field - The COSMA study.

Science.gov (United States)

Bartels, Susanne; Márki, Ferenc; Müller, Uwe

2015-12-15

Air traffic has increased for the past decades and is forecasted to continue to grow. Noise due to current airport operations can impair the physical and psychological well-being of airport residents. The field study investigated aircraft noise-induced short-term (i.e., within hourly intervals) annoyance in local residents near a busy airport. We aimed at examining the contribution of acoustical and non-acoustical factors to the annoyance rating. Across four days from getting up till going to bed, 55 residents near Cologne/Bonn Airport (M=46years, SD=14years, 34 female) rated their annoyance due to aircraft noise at hourly intervals. For each participant and each hour, 26 noise metrics from outdoor measurements and further 6 individualized metrics that took into account the sound attenuation due to each person's whereabouts in and around their homes were obtained. Non-acoustical variables were differentiated into situational factors (time of day, performed activity during past hour, day of the week) and personal factors (e.g., sensitivity to noise, attitudes, domestic noise insulation). Generalized Estimation Equations were applied for the development of a prediction model for annoyance. Acoustical factors explained only a small proportion (13.7%) of the variance in the annoyance ratings. The number of fly-overs predicted annoyance better than did equivalent and maximum sound pressure levels. The proportion of explained variance in annoyance rose considerably (to 27.6%) when individualized noise metrics as well as situational and personal variables were included in the prediction model. Consideration of noise metrics related to the number of fly-overs and individual adjustment of noise metrics can improve the prediction of short-term annoyance compared to models using equivalent outdoor levels only. Non-acoustical factors have remarkable impact not only on long-term annoyance as shown before but also on short-term annoyance judged in the home environment. Copyright

A Tunable Low Noise Active Bandpass Filter Using a Noise Canceling Technique

Directory of Open Access Journals (Sweden)

N. Soltani

2016-12-01

Full Text Available A monolithic tunable low noise active bandpass filter is presented in this study. Biasing voltages can control the center frequency and quality factor. By keeping the gain constant, the center frequency shift is 300 MHz. The quality factor can range from 90 to 290 at the center frequency. By using a noise cancelling circuit, noise is kept lower than 2.8 dB. The proposed filter is designed using MMIC technology with a center frequency of 2.4 GHz and a power consumption of 180 mW. ED02AH technology is used to simulate the circuit elements.

Residential traffic noise exposure and vestibular schwannoma - a Danish case-control study.

Science.gov (United States)

Roswall, Nina; Stangerup, Sven-Eric; Cayé-Thomasen, Per; Schüz, Joachim; Johansen, Christoffer; Jensen, Steen Solvang; Raaschou-Nielsen, Ole; Sørensen, Mette

2017-10-01

Few risk factors for sporadic vestibular schwannoma (VS) are known. Several studies have proposed an increased risk with occupational noise exposure, whereas no studies have investigated residential traffic noise exposure as a risk factor. The present study investigated if residential traffic noise was associated with vestibular schwannoma in a large, population-based Danish case-control study. We identified 1454 VS cases, age above 30 years at diagnosis, between 1990 and 2007. For each case, we selected two random population controls, matched on sex and year of birth. Road and railway traffic noise at the residence was calculated for all present and historical addresses between 1987 and index date. Associations between traffic noise and risk for VS were estimated using conditional logistic regression, adjusted for education, disposable personal income, cohabitation status, railway noise exposure, municipal population density, and municipal income. A two-year time-weighted mean road traffic noise exposure was associated with an adjusted odds ratio of 0.92 (0.82-1.03) for developing VS, per 10 dB increment. There was no clear trend in categorical analyses. Similarly, linear and categorical analyses of residential railway noise did not suggest an association. We found no interaction with demographics, year of diagnosis, individual and municipal socioeconomic variables, and railway noise exposure. The results did not differ by tumor side, spread or size. The present study does not suggest an association between residential traffic noise and VS.

The Role of MicroRNAs in Environmental Risk Factors, Noise-Induced Hearing Loss, and Mental Stress.

Science.gov (United States)

Miguel, Verónica; Cui, Julia Yue; Daimiel, Lidia; Espinosa-Díez, Cristina; Fernández-Hernando, Carlos; Kavanagh, Terrance J; Lamas, Santiago

2018-03-20

MicroRNAs (miRNAs) are important regulators of gene expression and define part of the epigenetic signature. Their influence on every realm of biomedicine is established and progressively increasing. The impact of environment on human health is enormous. Among environmental risk factors impinging on quality of life are those of chemical nature (toxic chemicals, heavy metals, pollutants, and pesticides) as well as those related to everyday life such as exposure to noise or mental and psychosocial stress. Recent Advances: This review elaborates on the relationship between miRNAs and these environmental risk factors. The most relevant facts underlying the role of miRNAs in the response to these environmental stressors, including redox regulatory changes and oxidative stress, are highlighted and discussed. In the cases wherein miRNA mutations are relevant for this response, the pertinent literature is also reviewed. We conclude that, even though in some cases important advances have been made regarding close correlations between specific miRNAs and biological responses to environmental risk factors, a need for prospective large-cohort studies is likely necessary to establish causative roles. Antioxid. Redox Signal. 28, 773-796.

Adaptive Neuro-Fuzzy Methodology for Noise Assessment of Wind Turbine

Science.gov (United States)

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method. PMID:25075621

Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

Directory of Open Access Journals (Sweden)

Shahaboddin Shamshirband

Full Text Available Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS. This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

Noise sensitivity, rather than noise level, predicts the non-auditory effects of noise in community samples: a population-based survey

Directory of Open Access Journals (Sweden)

Jangho Park

2017-04-01

Full Text Available Abstract Background Excessive noise affects human health and interferes with daily activities. Although environmental noise may not directly cause mental illness, it may accelerate and intensify the development of latent mental disorders. Noise sensitivity (NS is considered a moderator of non-auditory noise effects. In the present study, we aimed to assess whether NS is associated with non-auditory effects. Methods We recruited a community sample of 1836 residents residing in Ulsan and Seoul, South Korea. From July to November 2015, participants were interviewed regarding their demographic characteristics, socioeconomic status, medical history, and NS. The non-auditory effects of noise were assessed using the Center of Epidemiologic Studies Depression, Insomnia Severity index, State Trait Anxiety Inventory state subscale, and Stress Response Inventory-Modified Form. Individual noise levels were recorded from noise maps. A three-model multivariate logistic regression analysis was performed to identify factors that might affect psychiatric illnesses. Results Participants ranged in age from 19 to 91 years (mean: 47.0 ± 16.1 years, and 37.9% (n = 696 were male. Participants with high NS were more likely to have been diagnosed with diabetes and hyperlipidemia and to use psychiatric medication. The multivariable analysis indicated that even after adjusting for noise-related variables, sociodemographic factors, medical illness, and duration of residence, subjects in the high NS group were more than 2 times more likely to experience depression and insomnia and 1.9 times more likely to have anxiety, compared with those in the low NS group. Noise exposure level was not identified as an explanatory value. Conclusions NS increases the susceptibility and hence moderates there actions of individuals to noise. NS, rather than noise itself, is associated with an elevated susceptibility to non-auditory effects.

Noise-induced enhancement of network reciprocity in social dilemmas

International Nuclear Information System (INIS)

Zhang, Gui-Qing; Sun, Qi-Bo; Wang, Lin

2013-01-01

Highlights: • We introduce the noise-induced mechanism into the prisoner’s dilemma game. • Cooperation will be largely enhanced by introducing the noise into the calculation of fitness. • Despite the defectors prevail initially, the stressed factor still promotes the cooperation. • The mechanism studied here is helpful on different kinds of interaction networks. -- Abstract: The network reciprocity is an important dynamic rule fostering the emergence of cooperation among selfish individuals. This was reported firstly in the seminal work of Nowak and May, where individuals were arranged on the regular lattice network, and played the prisoner’s dilemma game (PDG). In the standard PDG, one often assumes that the players have perfect rationality. However, in reality, we human are far from rational agents, as we often make mistakes, and behave irrationally. Accordingly, in this work, we introduce the element of noise into the measurement of fitness, which is determined by the parameter α controlling the degree of noise. The considered noise-induced mechanism remarkably promotes the behavior of cooperation, which may be conducive to interpret the emergence of cooperation within the population

What Do Contrast Threshold Equivalent Noise Studies Actually Measure? Noise vs. Nonlinearity in Different Masking Paradigms.

Directory of Open Access Journals (Sweden)

Alex S Baldwin

Full Text Available The internal noise present in a linear system can be quantified by the equivalent noise method. By measuring the effect that applying external noise to the system's input has on its output one can estimate the variance of this internal noise. By applying this simple "linear amplifier" model to the human visual system, one can entirely explain an observer's detection performance by a combination of the internal noise variance and their efficiency relative to an ideal observer. Studies using this method rely on two crucial factors: firstly that the external noise in their stimuli behaves like the visual system's internal noise in the dimension of interest, and secondly that the assumptions underlying their model are correct (e.g. linearity. Here we explore the effects of these two factors while applying the equivalent noise method to investigate the contrast sensitivity function (CSF. We compare the results at 0.5 and 6 c/deg from the equivalent noise method against those we would expect based on pedestal masking data collected from the same observers. We find that the loss of sensitivity with increasing spatial frequency results from changes in the saturation constant of the gain control nonlinearity, and that this only masquerades as a change in internal noise under the equivalent noise method. Part of the effect we find can be attributed to the optical transfer function of the eye. The remainder can be explained by either changes in effective input gain, divisive suppression, or a combination of the two. Given these effects the efficiency of our observers approaches the ideal level. We show the importance of considering these factors in equivalent noise studies.

Shot noise of charge current in a quantum dot responded by rotating and oscillating magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Zhao, Hong-Kang, E-mail: zhaohonk@yahoo.com; Zou, Wei-Ke [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Chen, Qiao [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China)

2014-09-07

We have investigated the shot noise and Fano factor of the dynamic spin-polarized quantum dot under the perturbations of a rotating magnetic field (RMF), and an oscillating magnetic field (OMF) by employing the non-equilibrium Green's function approach. The shot noise is enhanced from sub-Poissonian to super-Poissonian due to the application of RMF and OMF, and it is controlled sensitively by the tilt angle θ of RMF. The magnitude of shot noise increases as the photon energy ℏω of OMF increases, and its valley eventually is reversed to peaks as the photon energy is large enough. Double-peak structure of Fano factor is exhibited as the frequency of OMF increases to cover a large regime. The Zeeman energy μ{sub 0}B{sub 0} acts as an effective gate bias to exhibit resonant behavior, and novel peak emerges associated with the applied OMF.

Noise characteristics of single-walled carbon nanotube network transistors

International Nuclear Information System (INIS)

Kim, Un Jeong; Kim, Kang Hyun; Kim, Kyu Tae; Min, Yo-Sep; Park, Wanjun

2008-01-01

The noise characteristics of randomly networked single-walled carbon nanotubes grown directly by plasma enhanced chemical vapor deposition (PECVD) are studied with field effect transistors (FETs). Due to the geometrical complexity of nanotube networks in the channel area and the large number of tube-tube/tube-metal junctions, the inverse frequency, 1/f, dependence of the noise shows a similar level to that of a single single-walled carbon nanotube transistor. Detailed analysis is performed with the parameters of number of mobile carriers and mobility in the different environment. This shows that the change in the number of mobile carriers resulting in the mobility change due to adsorption and desorption of gas molecules (mostly oxygen molecules) to the tube surface is a key factor in the 1/f noise level for carbon nanotube network transistors

Computation of unsteady flow and aerodynamic noise of NACA0018 airfoil using large-eddy simulation

Energy Technology Data Exchange (ETDEWEB)

Kim, H.-J. [Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of); Lee, S. [Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of)]. E-mail: sbaelee@inha.ac.kr; Fujisawa, N. [Department of Mechanical and Production Engineering, Niigata University, 8050 Ikarashi-2, Niigata 950-2181 (Japan)

2006-04-15

The flow field around a symmetrical NACA airfoil in the uniform flow under generation of noise was numerically studied. The numerical simulation was carried out by a large-eddy simulation that employs a deductive dynamic model as the subgrid-scale model. The results at small angle of attack {alpha} = 3-6{sup o} indicate that the discrete frequency noise is generated when the separated laminar flow reattaches near the trailing edge of pressure side and the strong instability thereafter affects positive vortices shed near the trailing edge. The quasi-periodic behavior of negative vortex formation on the suction side is affected by the strength and the periodicity of positive vortices near the trailing edge. The computation using aero-acoustic analogy indicates the primary discrete peak at the Strouhal frequency (=2f . {delta}/U ) of 0.15 by the vortex shedding from the trailing edge, which is in a close agreement with the experiment.

Noise sensitivity in relation to baseline arousal, physiological response and psychological features to noise exposure during task performance

NARCIS (Netherlands)

White, K.; Hofman, W.F.; van Kamp, I.

2010-01-01

People who consider themselves sensitive to noise, experience more noise annoyance, sleep disturbance and reduced daytime performance. Besides psychological factors, an association with cardiovascular reactions during noise has been established in noise sensitives. Decreased efficiency of the

Improving occupational conditions in coal preparation plants considering noise factor. [USSR

Energy Technology Data Exchange (ETDEWEB)

Zhurbinskii, L.F.; Shabel' nikova, E.V.; Sidorov, E.G.

1985-11-01

Three research institutes (IOTT, UkrNIIugleobogashchenie and KuzNIIugleobogashchenie) investigated health hazards associated with noise in coal preparation plants in the Donbass, Kuzbass and Karaganda basins. Investigations showed that there is a close correlation of noise pollution with rate of illness (heart diseases, nervous system diseases, alimentary duct diseases, respiratory diseases and diseases of the auditory organs). An equation which describes the correlation is derived. Correlation coefficient (ranging from 0.75 to 0.94) for each of 4 types of diseases was determined. Analyses showed that reducing noise level from 95 to 85 dB caused a decrease in rate of illness ranging from 2.5 to 3.0 times. Absenteeism due to illness decreased 1.5 to 2.0 times. Investigations also showed that accident rate is influenced by noise level. About 30% of accidents fell on working places with increased noise level. About 10% of accidents fell on working places with noise level of about 85 dB and from 3 to 4% accidents on working places with noise level of about 70 dB. Methods for noise pollution control in coal preparation plants in the USSR are evaluated. Effects of coal transport and handling on noise pollution in coal preparation plants are analyzed.

Effect of training data size and noise level on support vector machines virtual screening of genotoxic compounds from large compound libraries.

Science.gov (United States)

Kumar, Pankaj; Ma, Xiaohua; Liu, Xianghui; Jia, Jia; Bucong, Han; Xue, Ying; Li, Ze Rong; Yang, Sheng Yong; Wei, Yu Quan; Chen, Yu Zong

2011-05-01

Various in vitro and in-silico methods have been used for drug genotoxicity tests, which show limited genotoxicity (GT+) and non-genotoxicity (GT-) identification rates. New methods and combinatorial approaches have been explored for enhanced collective identification capability. The rates of in-silco methods may be further improved by significantly diversified training data enriched by the large number of recently reported GT+ and GT- compounds, but a major concern is the increased noise levels arising from high false-positive rates of in vitro data. In this work, we evaluated the effect of training data size and noise level on the performance of support vector machines (SVM) method known to tolerate high noise levels in training data. Two SVMs of different diversity/noise levels were developed and tested. H-SVM trained by higher diversity higher noise data (GT+ in any in vivo or in vitro test) outperforms L-SVM trained by lower noise lower diversity data (GT+ in in vivo or Ames test only). H-SVM trained by 4,763 GT+ compounds reported before 2008 and 8,232 GT- compounds excluding clinical trial drugs correctly identified 81.6% of the 38 GT+ compounds reported since 2008, predicted 83.1% of the 2,008 clinical trial drugs as GT-, and 23.96% of 168 K MDDR and 27.23% of 17.86M PubChem compounds as GT+. These are comparable to the 43.1-51.9% GT+ and 75-93% GT- rates of existing in-silico methods, 58.8% GT+ and 79% GT- rates of Ames method, and the estimated percentages of 23% in vivo and 31-33% in vitro GT+ compounds in the "universe of chemicals". There is a substantial level of agreement between H-SVM and L-SVM predicted GT+ and GT- MDDR compounds and the prediction from TOPKAT. SVM showed good potential in identifying GT+ compounds from large compound libraries based on higher diversity and higher noise training data.

Underwater noise modelling for environmental impact assessment

Energy Technology Data Exchange (ETDEWEB)

Farcas, Adrian [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom); Thompson, Paul M. [Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL (United Kingdom); Merchant, Nathan D., E-mail: nathan.merchant@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom)

2016-02-15

Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

Underwater noise modelling for environmental impact assessment

International Nuclear Information System (INIS)

Farcas, Adrian; Thompson, Paul M.; Merchant, Nathan D.

2016-01-01

Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

Noise-Induced Hearing Impairment As An Occupational Risk Factor ...

African Journals Online (AJOL)

Noise pollution in workplaces poses serious health risks including that of cardiovascular disturbances and impairment of hearing. The objective of this study was to assess the effects of occupational noise on hearing among selected industrial workers in Benin City, Nigeria. Male and female workers (n=150) in sawmills, ...

Prevalence and risk factors of noise-induced hearing loss among liquefied petroleum gas (LPG) cylinder infusion workers in Taiwan.

Science.gov (United States)

Chang, Shu-Ju; Chang, Chin-Kuo

2009-12-01

We assessed the exposure levels of noise, estimated prevalence, and identify risk factors of noise-induced hearing loss (NIHL) among male workers with a cross-sectional study in a liquefied petroleum gas cylinder infusion factory in Taipei City. Male in-field workers exposed to noise and administrative controls were enrolled in 2006 and 2007. Face-to-face interviews were applied for demographics, employment history, and drinking/smoking habit. We then performed the measurements on noise levels in field and administration area, and hearing thresholds on study subjects with standard apparatus and protocols. Existence of hearing loss > 25 dBHL for the average of 500 Hz, 1 kHz, and 2 kHz was accordingly determined for NIHL. The effects from noise exposure, predisposing characteristics, employment-related factors, and personal habits to NIHL were estimated by univariate and multivariate logistic regressions. A total of 75 subjects were involved in research and 56.8% of in-field workers had NIHL. Between the in-field and administration groups, hearing thresholds on the worse ear showed significant differences at frequencies of 4 k, 6 k, and 8 kHz with aging considered. Adjusted odds ratio for field noise exposure (OR=99.57, 95% CI: 3.53, 2,808.74) and frequent tea or coffee consumption (OR=0.03, 95% CI: 0.01, 0.51) were found significant. Current study addressed NIHL in a specific industry in Taiwan. Further efforts in minimizing its impact are still in need.

Quantum control with noisy fields: computational complexity versus sensitivity to noise

International Nuclear Information System (INIS)

Kallush, S; Khasin, M; Kosloff, R

2014-01-01

A closed quantum system is defined as completely controllable if an arbitrary unitary transformation can be executed using the available controls. In practice, control fields are a source of unavoidable noise, which has to be suppressed to retain controllability. Can one design control fields such that the effect of noise is negligible on the time-scale of the transformation? This question is intimately related to the fundamental problem of a connection between the computational complexity of the control problem and the sensitivity of the controlled system to noise. The present study considers a paradigm of control, where the Lie-algebraic structure of the control Hamiltonian is fixed, while the size of the system increases with the dimension of the Hilbert space representation of the algebra. We find two types of control tasks, easy and hard. Easy tasks are characterized by a small variance of the evolving state with respect to the operators of the control operators. They are relatively immune to noise and the control field is easy to find. Hard tasks have a large variance, are sensitive to noise and the control field is hard to find. The influence of noise increases with the size of the system, which is measured by the scaling factor N of the largest weight of the representation. For fixed time and control field the ability to control degrades as O(N) for easy tasks and as O(N 2 ) for hard tasks. As a consequence, even in the most favorable estimate, for large quantum systems, generic noise in the controls dominates for a typical class of target transformations, i.e. complete controllability is destroyed by noise. (paper)

Noise Considerations for V/STOL Transports

Science.gov (United States)

Kenyon, George C.

1968-01-01

Noise consideration may well be as important a factor in future aircraft concept selection as such economic factors as operating cost and profitability. The impact of noise on some of the design and operational aspects of future V/STOL transports is examined in detail, including consideration of configuration, attitude-control system, lift system, and terminal flight pattern. Extended vertical rise of VTOL aircraft as a method of limiting the intense noise exposure to the terminal area is shown to be only partially effective as well as costly. Comparisons are made of noise contours for conceptual V/STOL transports for several PNdB criteria. The variation in extent of affected area with configuration and criterion emphasizes the importance of establishing an "acceptable" noise level for "city-center" operation.

Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria

Science.gov (United States)

Dzhambov, Angel M; Dimitrova, Donka D

2016-01-01

Type 2 diabetes mellitus (T2DM) is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to Lden 71-80 dB (odds ratio (OR) = 4.49, 95% confidence interval (CI): 1.38, 14.68), fine particulate matter (PM)2.5 25.0-66.8 μg/m3 (OR = 1.32, 95% CI: 0.28, 6.24), benzo alpha pyrene 6.0-14.02 ng/m3 (OR = 1.76, 95% CI: 0.52, 5.98) and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07). Lden remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria. PMID:27157686

Occupational noise exposure and the risk of hypertension

DEFF Research Database (Denmark)

Stokholm, Zara A; Bonde, Jens Peter; Christensen, Kent L

2013-01-01

Noise may increase the risk of hypertension, but findings are inconsistent with respect to both community and occupational noise exposure. We used a large sample of noise-exposed industrial trades to analyze the association of occupational noise exposure and the risk of hypertension....

A transimpedance amplifier for excess noise measurements of high junction capacitance avalanche photodiodes

International Nuclear Information System (INIS)

Green, James E; David, John P R; Tozer, Richard C

2012-01-01

This paper reports a novel and versatile system for measuring excess noise and multiplication in avalanche photodiodes (APDs), using a bipolar junction transistor based transimpedance amplifier front-end and based on phase-sensitive detection, which permits accurate measurement in the presence of a high dark current. The system can reliably measure the excess noise factor of devices with capacitance up to 5 nF. This system has been used to measure thin, large area Si pin APDs and the resulting data are in good agreement with measurements of the same devices obtained from a different noise measurement system which will be reported separately. (paper)

Noise-induced hearing loss and associated factors among vector control workers in a Malaysian state.

Science.gov (United States)

Masilamani, Retneswari; Rasib, Abdul; Darus, Azlan; Ting, Anselm Su

2014-11-01

This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers. © 2012 APJPH.

Possibilities of an efficient noise damping in the large gas-fueled boilers

International Nuclear Information System (INIS)

1994-01-01

This report describes a series of tests with the objective to develop a technique for active control, and suppression of unstable conditions of combustion in gas-fired boiler systems. The primary target group for this report are persons within the energy sector, including especially users of natural gas. Focus has been given more to the practical possibilities and limitations than to complicated acoustical theory. The technical background for this work is constituted by the latest innovations within active noise cancelling methods for low frequent noise in channel- and pipe shaped systems, such as heating-, air-and exhaust systems. The fundamental idea has been to implement already functioning and commercial available systems for active noise cancellation in an modified setup to a gasfired boiler system. A few examples of similar attempts are given. Latest a relatively successful example of actively controlling an unstable combustion in a channel shaped burner system (CNRS Paris 1993). The conclusion of the project is anyway, that unstable combustion in larger gasfired boilers can not be controlled by the active methods and systems known today. The reasons for this are: the flame and thus the noise source are distributed in space, the acoustical wave-propagation in the combustion chamber is complex and with low damping, several loops for unstable combustion are possible. Within this project special sensors for high temperatures are developed, e.g.: probe microphones, high temperature turbulence screens and a system for measuring of the variations in UV-light emission form the flame. These systems are applicable also for more 'traditional active noise cancellation' of low-frequent noise in exhaust pipes and chimneys. (au)

Internal noise sources limiting contrast sensitivity.

Science.gov (United States)

Silvestre, Daphné; Arleo, Angelo; Allard, Rémy

2018-02-07

Contrast sensitivity varies substantially as a function of spatial frequency and luminance intensity. The variation as a function of luminance intensity is well known and characterized by three laws that can be attributed to the impact of three internal noise sources: early spontaneous neural activity limiting contrast sensitivity at low luminance intensities (i.e. early noise responsible for the linear law), probabilistic photon absorption at intermediate luminance intensities (i.e. photon noise responsible for de Vries-Rose law) and late spontaneous neural activity at high luminance intensities (i.e. late noise responsible for Weber's law). The aim of this study was to characterize how the impact of these three internal noise sources vary with spatial frequency and determine which one is limiting contrast sensitivity as a function of luminance intensity and spatial frequency. To estimate the impact of the different internal noise sources, the current study used an external noise paradigm to factorize contrast sensitivity into equivalent input noise and calculation efficiency over a wide range of luminance intensities and spatial frequencies. The impact of early and late noise was found to drop linearly with spatial frequency, whereas the impact of photon noise rose with spatial frequency due to ocular factors.

STUDY NOISE POLLUTION TYUMEN USING GIS

Directory of Open Access Journals (Sweden)

V. A. Dobryakova

2016-01-01

Full Text Available One of the most harmful factors of environment of the city is the noise, and its weight among the factors adversely affecting the life and health of the population has been increasing steadily [Sheina and etc., 2007; Polovinkina and etc., 2012]. Today, most major cities of the Russian Federation (70% have a high noise pollution problem. The system of support for the monitoring and control of acoustic situation in the city can be considered noise pollution electronic cards made using geographic information systems (GIS. There are two fundamentally different approaches to the selection of software for creation of noise maps. According to the first of them, use universal multifunctional complexes GIS (ArcGIS, MapInfo. According to the distribution of data points on the noise characteristics is created TIN model. A second approach to create noise maps using highly specialized software (MapNoise, SoundPLAN, Mitha, Cadna, ExNOISE et al.. To calculate noise propagation area is divided on the grid with a certain step, the most relevant mapping purposes. Calculation of noise levels is carried out in a grid cell by measurements based on diffraction and reflection of sound barriers and absorbing underlying surface. Noise pollution is also displayed using contour lines.

1/ f noise from the laws of thermodynamics for finite-size fluctuations.

Science.gov (United States)

Chamberlin, Ralph V; Nasir, Derek M

2014-07-01

Computer simulations of the Ising model exhibit white noise if thermal fluctuations are governed by Boltzmann's factor alone; whereas we find that the same model exhibits 1/f noise if Boltzmann's factor is extended to include local alignment entropy to all orders. We show that this nonlinear correction maintains maximum entropy during equilibrium fluctuations. Indeed, as with the usual way to resolve Gibbs' paradox that avoids entropy reduction during reversible processes, the correction yields the statistics of indistinguishable particles. The correction also ensures conservation of energy if an instantaneous contribution from local entropy is included. Thus, a common mechanism for 1/f noise comes from assuming that finite-size fluctuations strictly obey the laws of thermodynamics, even in small parts of a large system. Empirical evidence for the model comes from its ability to match the measured temperature dependence of the spectral-density exponents in several metals and to show non-Gaussian fluctuations characteristic of nanoscale systems.

Managing environmental noise in Hong Kong

Science.gov (United States)

Li, Kai Ming

2004-05-01

Hong Kong is well known for its economic vibrancy and its hyper densely population: more than 7 million people living in a total area of slightly over 1000 square kilometers of hilly areas. Most of these people live and work in about 20% of the total land area, resulting in probably the highest densities in the world. The high population density is also matched by a large number of vehicles running in the roads. At present, there are over 400000 vehicles operating on a highway network less than 1000 km in length. With all these factors plus many urban activities associated with the rapid growth and development, noise is an important environmental issue in the city. Although there are many dimensions for the quality of life, the acoustic environment is undoubtedly an essential part of it, especially when the people's aspirations increase as the society develops. This paper summarizes the development of strategies for controlling environmental noise in Hong Kong in the past two decades. The current situation will be addressed and a proposal for an improved traffic noise policy will be presented. [Work supported by the Research Grants Council, and The Hong Kong Polytechnic University.

Measurements techniques for transportation noise

International Nuclear Information System (INIS)

Brambilla, G.

2001-01-01

The noise from transport systems (roads, railways and aircraft) are increasing more and more both in space and in time and, therefore, they are still the major factor responsible for environmental noise pollution. The population exposed to transport noise is also increasing, and the corresponding health effects on people (i.e. annoyance and sleep disturbance) become more severe. Due to this current situation international and national legislation has been issued and implemented to reduce the harmful effects of such noise. This paper describes the techniques prescribed by recent Italian legislation to measure road, railway and aircraft noise. (author)

Self-reported sleep disturbances due to railway noise: exposure-response relationships for nighttime equivalent and maximum noise levels.

Science.gov (United States)

Aasvang, Gunn Marit; Moum, Torbjorn; Engdahl, Bo

2008-07-01

The objective of the present survey was to study self-reported sleep disturbances due to railway noise with respect to nighttime equivalent noise level (L(p,A,eq,night)) and maximum noise level (L(p,A,max)). A sample of 1349 people in and around Oslo in Norway exposed to railway noise was studied in a cross-sectional survey to obtain data on sleep disturbances, sleep problems due to noise, and personal characteristics including noise sensitivity. Individual noise exposure levels were determined outside of the bedroom facade, the most-exposed facade, and inside the respondents' bedrooms. The exposure-response relationships were analyzed by using logistic regression models, controlling for possible modifying factors including the number of noise events (train pass-by frequency). L(p,A,eq,night) and L(p,A,max) were significantly correlated, and the proportion of reported noise-induced sleep problems increased as both L(p,A,eq,night) and L(p,A,max) increased. Noise sensitivity, type of bedroom window, and pass-by frequency were significant factors affecting noise-induced sleep disturbances, in addition to the noise exposure level. Because about half of the study population did not use a bedroom at the most-exposed side of the house, the exposure-response curve obtained by using noise levels for the most-exposed facade underestimated noise-induced sleep disturbance for those who actually have their bedroom at the most-exposed facade.

Characterizing large river sounds: Providing context for understanding the environmental effects of noise produced by hydrokinetic turbines.

Science.gov (United States)

Bevelhimer, Mark S; Deng, Z Daniel; Scherelis, Constantin

2016-01-01

Underwater noise associated with the installation and operation of hydrokinetic turbines in rivers and tidal zones presents a potential environmental concern for fish and marine mammals. Comparing the spectral quality of sounds emitted by hydrokinetic turbines to natural and other anthropogenic sound sources is an initial step at understanding potential environmental impacts. Underwater recordings were obtained from passing vessels and natural underwater sound sources in static and flowing waters. Static water measurements were taken in a lake with minimal background noise. Flowing water measurements were taken at a previously proposed deployment site for hydrokinetic turbines on the Mississippi River, where sounds created by flowing water are part of all measurements, both natural ambient and anthropogenic sources. Vessel sizes ranged from a small fishing boat with 60 hp outboard motor to an 18-unit barge train being pushed upstream by tugboat. As expected, large vessels with large engines created the highest sound levels, which were, on average, 40 dB greater than the sound created by an operating hydrokinetic turbine. A comparison of sound levels from the same sources at different distances using both spherical and cylindrical sound attenuation functions suggests that spherical model results more closely approximate observed sound attenuation.

On common noise-induced synchronization in complex networks with state-dependent noise diffusion processes

Science.gov (United States)

Russo, Giovanni; Shorten, Robert

2018-04-01

This paper is concerned with the study of common noise-induced synchronization phenomena in complex networks of diffusively coupled nonlinear systems. We consider the case where common noise propagation depends on the network state and, as a result, the noise diffusion process at the nodes depends on the state of the network. For such networks, we present an algebraic sufficient condition for the onset of synchronization, which depends on the network topology, the dynamics at the nodes, the coupling strength and the noise diffusion. Our result explicitly shows that certain noise diffusion processes can drive an unsynchronized network towards synchronization. In order to illustrate the effectiveness of our result, we consider two applications: collective decision processes and synchronization of chaotic systems. We explicitly show that, in the former application, a sufficiently large noise can drive a population towards a common decision, while, in the latter, we show how common noise can synchronize a network of Lorentz chaotic systems.

Measured Noise from Small Unmanned Aerial Vehicles

Science.gov (United States)

Cabell, Randolph; McSwain, Robert; Grosveld, Ferdinand

2016-01-01

Proposed uses of small unmanned aerial vehicles (UAVs), including home package delivery, have the potential to expose large portions of communities to a new noise source. This paper discusses results of flyover noise measurements of four small UAVs, including an internal combustion-powered model airplane and three battery-powered multicopters. Basic noise characteristics of these vehicles are discussed, including spectral properties and sound level metrics such as sound pressure level, effective perceived noise level, and sound exposure level. The size and aerodynamic characteristics of the multicopters in particular make their flight path susceptible to atmospheric disturbances such as wind gusts. These gusts, coupled with a flight control system that varies rotor speed to maintain vehicle stability, create an unsteady acoustic signature. The spectral variations resulting from this unsteadiness are explored, in both hover and flyover conditions for the multicopters. The time varying noise, which differs from the relatively steady noise generated by large transport aircraft, may complicate the prediction of human annoyance using conventional sound level metrics.

Noise Stress Induces an Epidermal Growth Factor Receptor/Xeroderma Pigmentosum-A Response in the Auditory Nerve.

Science.gov (United States)

Guthrie, O'neil W

2017-03-01

In response to toxic stressors, cancer cells defend themselves by mobilizing one or more epidermal growth factor receptor (EGFR) cascades that employ xeroderma pigmentosum-A (XPA) to repair damaged genes. Recent experiments discovered that neurons within the auditory nerve exhibit basal levels of EGFR+XPA co-expression. This finding implied that auditory neurons in particular or neurons in general have the capacity to mobilize an EGFR+XPA defense. Therefore, the current study tested the hypothesis that noise stress would alter the expression pattern of EGFR/XPA within the auditory nerve. Design-based stereology was used to quantify the proportion of neurons that expressed EGFR, XPA, and EGFR+XPA with and without noise stress. The results revealed an intricate neuronal response that is suggestive of alterations to both co-expression and individual expression of EGFR and XPA. In both the apical and middle cochlear coils, the noise stress depleted EGFR+XPA expression. Furthermore, there was a reduction in the proportion of neurons that expressed XPA-alone in the middle coils. However, the noise stress caused a significant increase in the proportion of neurons that expressed EGFR-alone in the middle coils. The basal cochlear coils failed to mobilize a significant response to the noise stress. These results suggest that EGFR and XPA might be part of the molecular defense repertoire of the auditory nerve.

Noise Stress Induces an Epidermal Growth Factor Receptor/Xeroderma Pigmentosum–A Response in the Auditory Nerve

Science.gov (United States)

Guthrie, O’neil W.

2017-01-01

In response to toxic stressors, cancer cells defend themselves by mobilizing one or more epidermal growth factor receptor (EGFR) cascades that employ xeroderma pigmentosum–A (XPA) to repair damaged genes. Recent experiments discovered that neurons within the auditory nerve exhibit basal levels of EGFR+XPA co-expression. This finding implied that auditory neurons in particular or neurons in general have the capacity to mobilize an EGFR+XPA defense. Therefore, the current study tested the hypothesis that noise stress would alter the expression pattern of EGFR/XPA within the auditory nerve. Design-based stereology was used to quantify the proportion of neurons that expressed EGFR, XPA, and EGFR+XPA with and without noise stress. The results revealed an intricate neuronal response that is suggestive of alterations to both co-expression and individual expression of EGFR and XPA. In both the apical and middle cochlear coils, the noise stress depleted EGFR+XPA expression. Furthermore, there was a reduction in the proportion of neurons that expressed XPA-alone in the middle coils. However, the noise stress caused a significant increase in the proportion of neurons that expressed EGFR-alone in the middle coils. The basal cochlear coils failed to mobilize a significant response to the noise stress. These results suggest that EGFR and XPA might be part of the molecular defense repertoire of the auditory nerve. PMID:28056182

Observation of the fundamental Nyquist noise limit in an ultra-high Q-factor cryogenic bulk acoustic wave cavity

Energy Technology Data Exchange (ETDEWEB)

Goryachev, Maxim, E-mail: maxim.goryachev@uwa.edu.au; Ivanov, Eugene N.; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Kann, Frank van [School of Physics, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Galliou, Serge [Department of Time and Frequency, FEMTO-ST Institute, ENSMM, 26 Chemin de l' Épitaphe, 25000 Besançon (France)

2014-10-13

Thermal Nyquist noise fluctuations of high-Q bulk acoustic wave cavities have been observed at cryogenic temperatures with a DC superconducting quantum interference device amplifier. High Q modes with bandwidths of few tens of milliHz produce thermal fluctuations with a signal-to-noise ratio of up to 23 dB. The estimated effective temperature from the Nyquist noise is in good agreement with the physical temperature of the device, confirming the validity of the equivalent circuit model and the non-existence of any excess resonator self-noise. The measurements also confirm that the quality factor remains extremely high (Q > 10{sup 8} at low order overtones) for very weak (thermal) system motion at low temperatures, when compared to values measured with relatively strong external excitation. This result represents an enabling step towards operating such a high-Q acoustic device at the standard quantum limit.

Noise estimation for remote sensing image data analysis

Science.gov (United States)

Du, Qian

2004-01-01

Noise estimation does not receive much attention in remote sensing society. It may be because normally noise is not large enough to impair image analysis result. Noise estimation is also very challenging due to the randomness nature of the noise (for random noise) and the difficulty of separating the noise component from the signal in each specific location. We review and propose seven different types of methods to estimate noise variance and noise covariance matrix in a remotely sensed image. In the experiment, it is demonstrated that a good noise estimate can improve the performance of an algorithm via noise whitening if this algorithm assumes white noise.

Effect of Attitudinal, Situational and Demographic Factors on Annoyance Due to Environmental Vibration and Noise from Construction of a Light Rapid Transit System

Directory of Open Access Journals (Sweden)

Daniel Wong-McSweeney

2016-12-01

Full Text Available The aim of this paper is to determine what non-exposure factors influence the relationship between vibration and noise exposure from the construction of a Light Rapid Transit (LRT system and the annoyance of nearby residents. Noise and vibration from construction sites are known to annoy residents, with annoyance increasing as a function of the magnitude of the vibration and noise. There is not a strong correlation between exposure and levels of annoyance suggesting that factors not directly related to the exposure may have an influence. A range of attitudinal, situational and demographic factors are investigated with the aim of understanding the wide variation in annoyance for a given vibration exposure. A face-to-face survey of residents (n = 350 near three sites of LRT construction was conducted, and responses were compared to semi-empirical estimates of the internal vibration within the buildings. It was found that annoyance responses due to vibration were strongly influenced by two attitudinal variables, concern about property damage and sensitivity to vibration. Age, ownership of the property and the visibility of the construction site were also important factors. Gender, time at home and expectation of future levels of vibration had much less influence. Due to the measurement methods used, it was not possible to separate out the effects of noise and vibration on annoyance; as such, this paper focusses on annoyance due to vibration exposure. This work concludes that for the most cost-effective reduction of the impact of construction vibration and noise on the annoyance felt by a community, policies should consider attitudinal factors.

Modeling Random Telegraph Noise Under Switched Bias Conditions Using Cyclostationary RTS Noise

NARCIS (Netherlands)

van der Wel, A.P.; Klumperink, Eric A.M.; Vandamme, L.K.J.; Nauta, Bram

In this paper, we present measurements and simulation of random telegraph signal (RTS) noise in n-channel MOSFETs under periodic large signal gate-source excitation (switched bias conditions). This is particularly relevant to analog CMOS circuit design where large signal swings occur and where LF

1/f noise in carbon nanotubes

International Nuclear Information System (INIS)

Collins, Philip G.; Fuhrer, M. S.; Zettl, A.

2000-01-01

The electrical noise characteristics of single-walled carbon nanotubes have been investigated. For all three cases of individual isolated nanotubes, thin films of interconnected nanotubes, and bulk nanotube mats, anomalously large bias-dependent 1/f noise is found. The noise magnitude greatly exceeds that commonly observed in metal films, carbon resistors, or even carbon fibers with comparable resistances. A single empirical expression describes the noise for all nanotube samples, suggesting a common noise-generating mechanism proportional only to the number of nanotubes in the conductor. We consider likely sources of the fluctuations, and consequences for electronic applications of nanotubes if the excessive noise cannot be suppressed. (c) 2000 American Institute of Physics

Perceptual effects of noise reduction by time-frequency masking of noisy speech.

Science.gov (United States)

Brons, Inge; Houben, Rolph; Dreschler, Wouter A

2012-10-01

Time-frequency masking is a method for noise reduction that is based on the time-frequency representation of a speech in noise signal. Depending on the estimated signal-to-noise ratio (SNR), each time-frequency unit is either attenuated or not. A special type of a time-frequency mask is the ideal binary mask (IBM), which has access to the real SNR (ideal). The IBM either retains or removes each time-frequency unit (binary mask). The IBM provides large improvements in speech intelligibility and is a valuable tool for investigating how different factors influence intelligibility. This study extends the standard outcome measure (speech intelligibility) with additional perceptual measures relevant for noise reduction: listening effort, noise annoyance, speech naturalness, and overall preference. Four types of time-frequency masking were evaluated: the original IBM, a tempered version of the IBM (called ITM) which applies limited and non-binary attenuation, and non-ideal masking (also tempered) with two different types of noise-estimation algorithms. The results from ideal masking imply that there is a trade-off between intelligibility and sound quality, which depends on the attenuation strength. Additionally, the results for non-ideal masking suggest that subjective measures can show effects of noise reduction even if noise reduction does not lead to differences in intelligibility.

Filtering out the noise: evaluating the impact of noise and sound reduction strategies on sleep quality for ICU patients.

Science.gov (United States)

Bosma, Karen J; Ranieri, V Marco

2009-01-01

The review article by Xie and colleagues examines the impact of noise and noise reduction strategies on sleep quality for critically ill patients. Evaluating the impact of noise on sleep quality is challenging, as it must be measured relative to other factors that may be more or less disruptive to patients' sleep. Such factors may be difficult for patients, observers, and polysomnogram interpreters to identify, due to our limited understanding of the causes of sleep disruption in the critically ill, as well as the challenges in recording and quantifying sleep stages and sleep fragmentation in the intensive care unit. Furthermore, most research in this field has focused on noise level, whereas acousticians typically evaluate additional parameters such as noise spectrum and reverberation time. The authors highlight the disparate results and limitations of existing studies, including the lack of attention to other acoustic parameters besides sound level, and the combined effects of different sleep disturbing factors.

The Effects of Background Noise on the Performance of an Automatic Speech Recogniser

Science.gov (United States)

Littlefield, Jason; HashemiSakhtsari, Ahmad

2002-11-01

Ambient or environmental noise is a major factor that affects the performance of an automatic speech recognizer. Large vocabulary, speaker-dependent, continuous speech recognizers are commercially available. Speech recognizers, perform well in a quiet environment, but poorly in a noisy environment. Speaker-dependent speech recognizers require training prior to them being tested, where the level of background noise in both phases affects the performance of the recognizer. This study aims to determine whether the best performance of a speech recognizer occurs when the levels of background noise during the training and test phases are the same, and how the performance is affected when the levels of background noise during the training and test phases are different. The relationship between the performance of the speech recognizer and upgrading the computer speed and amount of memory as well as software version was also investigated.

Impact of traffic noise on railway traffic safety

Directory of Open Access Journals (Sweden)

Zdravko TOŠ

2008-01-01

Full Text Available Traffic noise is one of the dominant factors of ergo-assessment. The harmful impact of traffic noise on the engine driver as target group can be studied in isolation from other ergo-assessment factors only in the initial phase of research. The simultaneous action of several related factors in the system of ergo-assessment factors has cumulative effect on the perception and psychomotoric status of the railway traffic participants in the appropriate traffic situation. The initial partial research of traffic noise by a combination of several scientific methods needs to be eventually upgraded by studying the relations among several concurrent important or dominant ergo-assessment factors.

Lexical tone recognition in noise in normal-hearing children and prelingually deafened children with cochlear implants.

Science.gov (United States)

Mao, Yitao; Xu, Li

2017-01-01

The purpose of the present study was to investigate Mandarin tone recognition in background noise in children with cochlear implants (CIs), and to examine the potential factors contributing to their performance. Tone recognition was tested using a two-alternative forced-choice paradigm in various signal-to-noise ratio (SNR) conditions (i.e. quiet, +12, +6, 0, and -6 dB). Linear correlation analysis was performed to examine possible relationships between the tone-recognition performance of the CI children and the demographic factors. Sixty-six prelingually deafened children with CIs and 52 normal-hearing (NH) children as controls participated in the study. Children with CIs showed an overall poorer tone-recognition performance and were more susceptible to noise than their NH peers. Tone confusions between Mandarin tone 2 and tone 3 were most prominent in both CI and NH children except for in the poorest SNR conditions. Age at implantation was significantly correlated with tone-recognition performance of the CI children in noise. There is a marked deficit in tone recognition in prelingually deafened children with CIs, particularly in noise listening conditions. While factors that contribute to the large individual differences are still elusive, early implantation could be beneficial to tone development in pediatric CI users.

Fast, noise-free memory for photon synchronization at room temperature.

Science.gov (United States)

Finkelstein, Ran; Poem, Eilon; Michel, Ohad; Lahad, Ohr; Firstenberg, Ofer

2018-01-01

Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. We demonstrate a fast ladder memory (FLAME) mapping the optical field onto the superposition between electronic orbitals of rubidium vapor. Using a ladder-level system of orbital transitions with nearly degenerate frequencies simultaneously enables high bandwidth, low noise, and long memory lifetime. We store and retrieve 1.7-ns-long pulses, containing 0.5 photons on average, and observe short-time external efficiency of 25%, memory lifetime (1/ e ) of 86 ns, and below 10 -4 added noise photons. Consequently, coupling this memory to a probabilistic source would enhance the on-demand photon generation probability by a factor of 12, the highest number yet reported for a noise-free, room temperature memory. This paves the way toward the controlled production of large quantum states of light from probabilistic photon sources.

Noise as a Health Hazard for Children, Time to Make a Noise about it.

Science.gov (United States)

Thakur, Neha; Batra, Prerna; Gupta, Piyush

2016-02-01

Noise, a modern day curse of advancing infrastructure and technology, has emerged as an important public health problem. Exposure to noise during pregnancy may result in high-frequency hearing loss in newborns, growth retardation, cochlear damage, prematurity and birth defects. Newborns exposed to sound above 45 decibels may experience increase in blood pressure, heart rate, respiratory rate; decreased oxygen saturation; and increased caloric consumption. Noise exposure in older children may result in learning disabilities, attention difficulties, insulin resistance, hypertension, stress ulcers and cardiovascular diseases. Sudden exposure to loud noise can lead to rupture of eardrum. The damaging effects of noise pollution are more noticeable in large metropolitan cities, the hubs of urban settlements and industrial growth. Another concern is noise pollution inside the hospitals (particularly intensive care areas) that can lead to serious health consequences both for caregivers and for children. The issue needs to be addressed by both researchers and policy makers on an urgent basis.

Comparison of Speech Perception in Background Noise with Acceptance of Background Noise in Aided and Unaided Conditions.

Science.gov (United States)

Nabelek, Anna K.; Tampas, Joanna W.; Burchfield, Samuel B.

2004-01-01

l, speech perception in noiseBackground noise is a significant factor influencing hearing-aid satisfaction and is a major reason for rejection of hearing aids. Attempts have been made by previous researchers to relate the use of hearing aids to speech perception in noise (SPIN), with an expectation of improved speech perception followed by an…

Application of GIS in Urban Traffic Noise Pollution

OpenAIRE

Manouchehr Omidvari; Ali Asghar Alesheikh

2010-01-01

Large urban areas are facing growing problems of noise pollutions. Geospatial Information Systems (GIS) can conveniently be adapted to gather, analyze and present noise information. GIS can also be extended to answer to user specific problems through deterministic and statistics models. The objectives of this research were to measure urban traffic noise levels, analyze temporal and spatial dynamics of urban traffic-induced noise pollution in the first districted of Tehran estimate the noise f...

Noise in secondary electron emission: the low yield case

Czech Academy of Sciences Publication Activity Database

Frank, Luděk

2005-01-01

Roč. 54, č. 4 (2005), s. 361-365 ISSN 0022-0744 R&D Projects: GA AV ČR(CZ) IAA1065304 Keywords : secondary electrons * noise * SEM image noise * secondary emission noise * statistics of secondary electrons * non-Poisson factor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.720, year: 2005

In-plant noise as occupational risk factor at petrochemical plants

Directory of Open Access Journals (Sweden)

A.D. Volgareva

2017-03-01

Full Text Available The article summarizes the data obtained in long-term research on working conditions estimates and studying damages to hearing organs in workers employed at petrochemical plants. We chose workers employed at five basic organic synthesis productions as an object of our study; these productions include ethylene-propylene, ethylbenzene-styrene, organic alcohols production (butanol and 2-ethylhexanol, phthalic anhydride. We detected that heating furnaces, compressors, and pumps were the main noise sources at the examined productions. Our research revealed that noise levels at the examined productions varied from 60 to 99 decibel, and calculated equivalent noise levels reached the 3 hazard class with 1st and 2nd hazard degree. Audiometric research showed that signs of impacts exerted by noise on hearing organs of workers belonging to basic occupational groups (processing machine operators and pumps and compressor operators occurred authentically more frequently than in case of control equipment mechanics and automatic equipment operators (comparison group (<0,001. The highest risk of occupational hearing loss was detected for drivers while the same pathology evolved 1.5–2.0 times less frequently in processing machines operators. Frequency of hearing organs damage in all basic occupational groups authentically increased as working period grew. Signs of such damage increased dramatically in processing machines operators' group after 10 years of work but still the overall level was slightly lower than in drivers' group. It is shown that the most efficient measures of collective protection aimed at noise reduction are application of low-noise technological equipment, acoustic protection (sound insulation and sound absorption, etc, remote control, as well as rational labor and leisure regime. Medical care and vocational rehabilitation of people with occupational hearing loss also contribute significantly into sensory deafness prevention.

Assessing effects of military aircraft noise on residential property values near airbases

Science.gov (United States)

Fidell, Sanford; Tabachnick, Barbara; Silvati, Laura; Cook, Brenda

The question, 'Does military aircraft noise exposure affect residential property values in the vicinity of Air Force bases?', can be asked and answered with varying degrees of generality and tolerable errors of inference. Definitive answers are difficult to develop because the question itself may not be meaningful in some circumstances: property values are affected by many factors other than aircraft noise which can fluctuate greatly in different areas and during different time periods; credible attribution of causality for changes in property values uniquely to aircraft noise requires many costly study design measures; and prior findings suggest that if a relationship exists, it is not a large or especially strong one. Thus, evidence of a simple geographic association between aircraft noise exposure and residential property values does not provide a conclusive answer to the question. In an effort to develop more compelling evidence, the US Air Force is planning to compare historical records of sale prices of properties in areas of differential aircraft noise exposure during specific time periods with predictions of sale prices derived from a validated statistical model of residential property values.

Interferometric constraints on quantum geometrical shear noise correlations

Energy Technology Data Exchange (ETDEWEB)

Chou, Aaron; Glass, Henry; Richard Gustafson, H.; Hogan, Craig J.; Kamai, Brittany L.; Kwon, Ohkyung; Lanza, Robert; McCuller, Lee; Meyer, Stephan S.; Richardson, Jonathan W.; Stoughton, Chris; Tomlin, Ray; Weiss, Rainer

2017-07-20

Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry---those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.

Electronic quantum noise and microwave photons

International Nuclear Information System (INIS)

Bize-Reydellet, L.H.

2003-06-01

This work is devoted to the experimental study of quantum electronic noise in mesoscopic conductors. In the first part of this thesis, we studied shot noise in a one-dimensional ballistic conductor: a quantum point contact (QPC). We showed experimentally that, when one of the QPC contacts is irradiated with microwave photons, we observe partition noise in the absence of net current flowing through the sample. Thus, we validate the scattering theory of photo-assisted shot noise first by measuring the Fano factor without bias voltage across the conductor, and then by measuring shot noise in the doubly non equilibrium situation, where both a bias voltage and a microwave modulation are applied. In the second part, we realized the first tests of a new experimental set-up which will be able to measure high frequency noise of a mesoscopic conductor and the photon statistics emitted by this conductor in the measurement circuit. These tests consist in realizing Hanbury-Brown and Twiss type experiments (intensity interferometry) with two kinds of microwave photon source. First, we used a thermal incoherent source (macroscopic 50 Ohms resistor). It showed super-Poissonian noise, since the power fluctuations are proportional to the square of the mean photon power. Secondly, we studied a classical monochromatic source, which shows a Poissonian statistics. The giant Fano factor measured is perfectly explained by the attenuator and amplifier noise. (author)

Type of activity and order of experimental conditions affect noise annoyance by identifiable and unidentifiable transportation noise.

Science.gov (United States)

White, Kim; Bronkhorst, Adelbert W; Meeter, Martijn

2018-04-01

Previous studies have shown that identifiability of sound sources influence noise annoyance levels. The aim of the present experiment was to additionally study the effects of actively performing a task versus a less active pastime on noise annoyance. This was done by asking participants to perform a task (task condition) or read a magazine of their choice (no-task condition), while listening to identifiable and unidentifiable samples of transportation noise at varying sound exposure levels (55-85 ASEL). Annoyance was higher for identifiable samples (recordings) than for unidentifiable transformed samples (with equal spectral energy and envelope). Although there was no main effect of activity type on noise annoyance, for the transformed samples, an interaction was found between activity type and sound exposure levels: annoyance started lower in the no-task condition, but rose more steeply with ascending exposure levels than was the case during task performance (large effect). When assessing order effects, it was found that annoyance was higher when the task condition came first, especially for lower sound exposure levels (large effects). It is therefore concluded that the type of activity and the condition order do influence noise annoyance but in interaction with exposure levels, the type of noise and habituation.

Development of HgCdTe large format MBE arrays and noise-free high speed MOVPE EAPD arrays for ground based NIR astronomy

Science.gov (United States)

Finger, G.; Baker, I.; Downing, M.; Alvarez, D.; Ives, D.; Mehrgan, L.; Meyer, M.; Stegmeier, J.; Weller, H. J.

2017-11-01

Large format near infrared HgCdTe 2Kx2K and 4Kx4K MBE arrays have reached a level of maturity which meets most of the specifications required for near infrared (NIR) astronomy. The only remaining problem is the persistence effect which is device specific and not yet fully under control. For ground based multi-object spectroscopy on 40 meter class telescopes larger pixels would be advantageous. For high speed near infrared fringe tracking and wavefront sensing the only way to overcome the CMOS noise barrier is the amplification of the photoelectron signal inside the infrared pixel by means of the avalanche gain. A readout chip for a 320x256 pixel HgCdTe eAPD array will be presented which has 32 parallel video outputs being arranged in such a way that the full multiplex advantage is also available for small sub-windows. In combination with the high APD gain this allows reducing the readout noise to the subelectron level by applying nondestructive readout schemes with subpixel sampling. Arrays grown by MOVPE achieve subelectron readout noise and operate with superb cosmetic quality at high APD gain. Efforts are made to reduce the dark current of those arrays to make this technology also available for large format focal planes of NIR instruments offering noise free detectors for deep exposures. The dark current of the latest MOVPE eAPD arrays is already at a level adequate for noiseless broad and narrow band imaging in scientific instruments.

Passerine birds breeding under chronic noise experience reduced fitness.

Directory of Open Access Journals (Sweden)

Julia Schroeder

Full Text Available BACKGROUND: Fitness in birds has been shown to be negatively associated with anthropogenic noise, but the underlying mechanisms remain obscure. It is however crucial to understand the mechanisms of how urban noise impinges on fitness to obtain a better understanding of the role of chronic noise in urban ecology. Here, we examine three hypotheses on how noise might reduce reproductive output in passerine birds: (H1 by impairing mate choice, (H2 by reducing territory quality and (H3 by impeding chick development. METHODOLOGY/PRINCIPAL FINDINGS: We used long-term data from an island population of house sparrows, Passer domesticus, in which we can precisely estimate fitness. We found that nests in an area affected by the noise from large generators produced fewer young, of lower body mass, and fewer recruits, even when we corrected statistically for parental genetic quality using a cross-fostering set-up, supporting H3. Also, individual females provided their young with food less often when they bred in the noisy area compared to breeding attempts by the same females elsewhere. Furthermore, we show that females reacted flexibly to increased noise levels by adjusting their provisioning rate in the short term, which suggests that noise may be a causal factor that reduces reproductive output. We rejected H1 and H2 because nestbox occupancy, parental body mass, age and reproductive investment did not differ significantly between noisy and quiet areas. CONCLUSIONS/SIGNIFICANCE: OUR RESULTS SUGGEST A PREVIOUSLY UNDESCRIBED MECHANISM TO EXPLAIN HOW ENVIRONMENTAL NOISE CAN REDUCE FITNESS IN PASSERINE BIRDS: by acoustically masking parent-offspring communication. More importantly, using a cross-fostering set-up, our results demonstrate that birds breeding in a noisy environment experience significant fitness costs. Chronic noise is omnipresent around human habitation and may produces similar fitness consequences in a wide range of urban bird species.

LTD windows of the STDP learning rule and synaptic connections having a large transmission delay enable robust sequence learning amid background noise.

Science.gov (United States)

Hayashi, Hatsuo; Igarashi, Jun

2009-06-01

Spike-timing-dependent synaptic plasticity (STDP) is a simple and effective learning rule for sequence learning. However, synapses being subject to STDP rules are readily influenced in noisy circumstances because synaptic conductances are modified by pre- and postsynaptic spikes elicited within a few tens of milliseconds, regardless of whether those spikes convey information or not. Noisy firing existing everywhere in the brain may induce irrelevant enhancement of synaptic connections through STDP rules and would result in uncertain memory encoding and obscure memory patterns. We will here show that the LTD windows of the STDP rules enable robust sequence learning amid background noise in cooperation with a large signal transmission delay between neurons and a theta rhythm, using a network model of the entorhinal cortex layer II with entorhinal-hippocampal loop connections. The important element of the present model for robust sequence learning amid background noise is the symmetric STDP rule having LTD windows on both sides of the LTP window, in addition to the loop connections having a large signal transmission delay and the theta rhythm pacing activities of stellate cells. Above all, the LTD window in the range of positive spike-timing is important to prevent influences of noise with the progress of sequence learning.

Low noise signal-to-noise ratio enhancing readout circuit for current-mediated active pixel sensors

International Nuclear Information System (INIS)

Ottaviani, Tony; Karim, Karim S.; Nathan, Arokia; Rowlands, John A.

2006-01-01

Diagnostic digital fluoroscopic applications continuously expose patients to low doses of x-ray radiation, posing a challenge to both the digital imaging pixel and readout electronics when amplifying small signal x-ray inputs. Traditional switch-based amorphous silicon imaging solutions, for instance, have produced poor signal-to-noise ratios (SNRs) at low exposure levels owing to noise sources from the pixel readout circuitry. Current-mediated amorphous silicon pixels are an improvement over conventional pixel amplifiers with an enhanced SNR across the same low-exposure range, but whose output also becomes nonlinear with increasing dosage. A low-noise SNR enhancing readout circuit has been developed that enhances the charge gain of the current-mediated active pixel sensor (C-APS). The solution takes advantage of the current-mediated approach, primarily integrating the signal input at the desired frequency necessary for large-area imaging, while adding minimal noise to the signal readout. Experimental data indicates that the readout circuit can detect pixel outputs over a large bandwidth suitable for real-time digital diagnostic x-ray fluoroscopy. Results from hardware testing indicate that the minimum achievable C-APS output current that can be discerned at the digital fluoroscopic output from the enhanced SNR readout circuit is 0.341 nA. The results serve to highlight the applicability of amorphous silicon current-mediated pixel amplifiers for large-area flat panel x-ray imagers

Novel Acoustic Feedback Cancellation Approaches In Hearing Aid Applications Using Probe Noise and Probe Noise Enhancement

DEFF Research Database (Denmark)

Guo, Meng; Jensen, Søren Holdt; Jensen, Jesper

2012-01-01

. In many cases, this bias problem causes the cancellation system to fail. The traditional probe noise approach, where a noise signal is added to the loudspeaker signal can, in theory, prevent the bias. However, in practice, the probe noise level must often be so high that the noise is clearly audible...... and annoying; this makes the traditional probe noise approach less useful in practical applications. In this work, we explain theoretically the decreased convergence rate when using low-level probe noise in the traditional approach, before we propose and study analytically two new probe noise approaches...... the proposed approaches much more attractive in practical applications. We demonstrate this through a simulation experiment with audio signals in a hearing aid acoustic feedback cancellation system, where the convergence rate is improved by as much as a factor of 10....

Examining nocturnal railway noise and aircraft noise in the field: sleep, psychomotor performance, and annoyance.

Science.gov (United States)

Elmenhorst, Eva-Maria; Pennig, Sibylle; Rolny, Vinzent; Quehl, Julia; Mueller, Uwe; Maaß, Hartmut; Basner, Mathias

2012-05-01

Traffic noise is interfering during day- and nighttime causing distress and adverse physiological reactions in large parts of the population. Railway noise proved less annoying than aircraft noise in surveys which were the bases for a so called 5 dB railway bonus regarding noise protection in many European countries. The present field study investigated railway noise-induced awakenings during sleep, nighttime annoyance and the impact on performance the following day. Comparing these results with those from a field study on aircraft noise allowed for a ranking of traffic modes concerning physiological and psychological reactions. 33 participants (mean age 36.2 years ± 10.3 (SD); 22 females) living alongside railway tracks around Cologne/Bonn (Germany) were polysomnographically investigated. These data were pooled with data from a field study on aircraft noise (61 subjects) directly comparing the effects of railway and aircraft noise in one random subject effects logistic regression model. Annoyance was rated in the morning evaluating the previous night. Probability of sleep stage changes to wake/S1 from railway noise increased significantly from 6.5% at 35 dB(A) to 20.5% at 80 dB(A) LAFmax. Rise time of noise events had a significant impact on awakening probability. Nocturnal railway noise led to significantly higher awakening probabilities than aircraft noise, partly explained by the different rise times, whereas the order was inversed for annoyance. Freight train noise compared to passenger train noise proved to have the most impact on awakening probability. Nocturnal railway noise had no effect on psychomotor vigilance. Nocturnal freight train noise exposure in Germany was associated with increased awakening probabilities exceeding those for aircraft noise and contrasting the findings of many annoyance surveys and annoyance ratings of our study. During nighttime a bonus for railway noise seems not appropriate. Copyright © 2012 Elsevier B.V. All rights reserved.

Dichotomous noise models of gene switches

Energy Technology Data Exchange (ETDEWEB)

Potoyan, Davit A., E-mail: potoyan@rice.edu; Wolynes, Peter G., E-mail: pwolynes@rice.edu [Department of Chemistry and Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005 (United States)

2015-11-21

Molecular noise in gene regulatory networks has two intrinsic components, one part being due to fluctuations caused by the birth and death of protein or mRNA molecules which are often present in small numbers and the other part arising from gene state switching, a single molecule event. Stochastic dynamics of gene regulatory circuits appears to be largely responsible for bifurcations into a set of multi-attractor states that encode different cell phenotypes. The interplay of dichotomous single molecule gene noise with the nonlinear architecture of genetic networks generates rich and complex phenomena. In this paper, we elaborate on an approximate framework that leads to simple hybrid multi-scale schemes well suited for the quantitative exploration of the steady state properties of large-scale cellular genetic circuits. Through a path sum based analysis of trajectory statistics, we elucidate the connection of these hybrid schemes to the underlying master equation and provide a rigorous justification for using dichotomous noise based models to study genetic networks. Numerical simulations of circuit models reveal that the contribution of the genetic noise of single molecule origin to the total noise is significant for a wide range of kinetic regimes.

Subjective assessment of simulated helicopter blade-slap noise

Science.gov (United States)

Lawton, B. W.

1976-01-01

The effects of several characteristics of helicopter blade slap upon human annoyance are examined. Blade slap noise was simulated by using continuous and impulsive noises characterized by five parameters: The number of sine waves in a single impulse; the frequency of the sine waves; the impulse repetition frequency; the sound pressure level (SPL) of the continuous noise; and the idealized crest factor of the impulses. Ten second samples of noise were synthesized with each of the five parameters at representative levels. The annoyance of each noise was judged by 40 human subjects. Analysis of the subjective data indicated that each of the five parameters had a statistically significant effect upon the annoyance judgments. The impulse crest factor and SPL of the continuous noise had very strong positive relationships with annoyance. The other parameters had smaller, but still significant, effects upon the annoyance judgments.

Deep Neural Network Based Supervised Speech Segregation Generalizes to Novel Noises through Large-scale Training

Science.gov (United States)

2015-01-01

Table 2: Segregation results in terms of STOI on a variety of novel noises (SNR=-2 dB) Babble-20 Cafeteria Factory Babble-100 Living Room Cafe Park...NOISEX-92 corpus [13], and a living room, a cafe and a park noise from the DEMAND corpus [12]. To put the performance of the noise-independent model in

Influence of Personal Factors on Sound Perception and Overall Experience in Urban Green Areas. A Case Study of a Cycling Path Highly Exposed to Road Traffic Noise.

Science.gov (United States)

Aletta, Francesco; Van Renterghem, Timothy; Botteldooren, Dick

2018-05-30

In contemporary urban design, green public areas play a vital role. They have great societal value, but if exposed to undue environmental noise their restorative potential might be compromised. On the other hand, research has shown that the presence of greenery can moderate noise annoyance in areas with high sound levels, while personal factors are expected to play an important role too. A cycling path bordered by vegetation, but highly exposed to road traffic noise, was here considered as a case study. A sound perception survey was submitted to participants on site and they were subsequently sorted into groups according to their noise sensitivity, visual attention and attitude towards greenery. The aim of this study was testing whether these three personal factors could affect their noise perception and overall experience of the place. Results showed that people highly sensitive to noise and more sceptical towards greenery's potential as an environmental moderator reported worse soundscape quality, while visually attentive people reported better quality. These three personal factors were found to be statistically independent. This study shows that several person-related factors impact the assessment of the sound environment in green areas. Although the majority of the respondents benefit from the presence of visual green, policy-makers and planners should be aware that for a significant subset of the population, it should be accompanied by a tranquil soundscape to be fully appreciated.

Noise from wind turbines

Energy Technology Data Exchange (ETDEWEB)

Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

2002-02-01

A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

Background Noises Versus Intraseasonal Variation Signals: Small vs. Large Convective Cloud Objects From CERES Aqua Observations

Science.gov (United States)

Xu, Kuan-Man

2015-01-01

During inactive phases of Madden-Julian Oscillation (MJO), there are plenty of deep but small convective systems and far fewer deep and large ones. During active phases of MJO, a manifestation of an increase in the occurrence of large and deep cloud clusters results from an amplification of large-scale motions by stronger convective heating. This study is designed to quantitatively examine the roles of small and large cloud clusters during the MJO life cycle. We analyze the cloud object data from Aqua CERES (Clouds and the Earth's Radiant Energy System) observations between July 2006 and June 2010 for tropical deep convective (DC) and cirrostratus (CS) cloud object types according to the real-time multivariate MJO index, which assigns the tropics to one of the eight MJO phases each day. The cloud object is a contiguous region of the earth with a single dominant cloud-system type. The criteria for defining these cloud types are overcast footprints and cloud top pressures less than 400 hPa, but DC has higher cloud optical depths (=10) than those of CS (background noises resulting from various types of the tropical waves with different wavenumbers and propagation speeds/directions.

Relationship between exposure to multiple noise sources and noise annoyance

NARCIS (Netherlands)

Miedema, H.M.E.

2004-01-01

Relationships between exposure to noise [metric: day-night level (DNL) or day-evening-night level (DENL)] from a single source (aircraft, road traffic, or railways) and annoyance based on a large international dataset have been published earlier. Also for stationary sources relationships have been

[The noise factor in the manufacture of chocolate and pastry products].

Science.gov (United States)

Tsvetkov, D; Kalburova, F

1988-01-01

Studies are performed on the noise and vibration condition and hearing in women workers in enterprises for confectionery. It is established that the noise is leading occupational hazard in the working environment and in half of the working places significantly surpasses the sanitary norms and the peak values reach sometimes to 102-105 db/A. Especially intensive sources of noise are some machines and industrial operations-vibratory tables, mixers, cocoa-rollers, grinder for sugar and cocoa, the operation "hammering of forms". The vibrations (general) are rarely met hazard in industry. A considerable decrease of hearing in the examined women workers is established.

Research status on aero-acoustic noise from wind turbine blades

International Nuclear Information System (INIS)

Yang, B

2013-01-01

This paper describes the noise mechanisms and categories of modern large wind turbine and main noise sources. Then the latest progresses in wind turbine noise researches are described from three aspects: noise prediction model, detection of noise sources by microphone array technique and methods for noise reduction. Although the turbine is restricted to horizontal axis wind turbines, the noise prediction model and reduction methods also can be applied to other turbines when the noise mechanisms are similar. Microphone array technique can be applied to locate any kind of noise sources

Interior noise analysis of a construction equipment cabin based on airborne and structure-borne noise predictions

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hee; Hong, Suk Yoon [Seoul National University, Seoul (Korea, Republic of); Song, Jee Hun [Chonnam National University, Gwangju (Korea, Republic of); Joo, Won Ho [Hyundai Heavy Industries Co. Ltd, Ulsan (Korea, Republic of)

2012-04-15

Noise from construction equipment affects not only surrounding residents, but also the operators of the machines. Noise that affects drivers must be evaluated during the preliminary design stage. This paper suggests an interior noise analysis procedure for construction equipment cabins. The analysis procedure, which can be used in the preliminary design stage, was investigated for airborne and structure borne noise. The total interior noise of a cabin was predicted from the airborne noise analysis and structure-borne noise analysis. The analysis procedure consists of four steps: modeling, vibration analysis, acoustic analysis and total interior noise analysis. A mesh model of a cabin for numerical analysis was made at the modeling step. At the vibration analysis step, the mesh model was verified and modal analysis and frequency response analysis are performed. At the acoustic analysis step, the vibration results from the vibration analysis step were used as initial values for radiated noise analysis and noise reduction analysis. Finally, the total cabin interior noise was predicted using the acoustic results from the acoustic analysis step. Each step was applied to a cabin of a middle-sized excavator and verified by comparison with measured data. The cabin interior noise of a middle-sized wheel loader and a large-sized forklift were predicted using the analysis procedure of the four steps and were compared with measured data. The interior noise analysis procedure of construction equipment cabins is expected to be used during the preliminary design stage.

Interior noise analysis of a construction equipment cabin based on airborne and structure-borne noise predictions

International Nuclear Information System (INIS)

Kim, Sung Hee; Hong, Suk Yoon; Song, Jee Hun; Joo, Won Ho

2012-01-01

Noise from construction equipment affects not only surrounding residents, but also the operators of the machines. Noise that affects drivers must be evaluated during the preliminary design stage. This paper suggests an interior noise analysis procedure for construction equipment cabins. The analysis procedure, which can be used in the preliminary design stage, was investigated for airborne and structure borne noise. The total interior noise of a cabin was predicted from the airborne noise analysis and structure-borne noise analysis. The analysis procedure consists of four steps: modeling, vibration analysis, acoustic analysis and total interior noise analysis. A mesh model of a cabin for numerical analysis was made at the modeling step. At the vibration analysis step, the mesh model was verified and modal analysis and frequency response analysis are performed. At the acoustic analysis step, the vibration results from the vibration analysis step were used as initial values for radiated noise analysis and noise reduction analysis. Finally, the total cabin interior noise was predicted using the acoustic results from the acoustic analysis step. Each step was applied to a cabin of a middle-sized excavator and verified by comparison with measured data. The cabin interior noise of a middle-sized wheel loader and a large-sized forklift were predicted using the analysis procedure of the four steps and were compared with measured data. The interior noise analysis procedure of construction equipment cabins is expected to be used during the preliminary design stage

Microphone directionality, pre-emphasis filter, and wind noise in cochlear implants.

Science.gov (United States)

Chung, King; McKibben, Nicholas

2011-10-01

Wind noise can be a nuisance or a debilitating masker for cochlear implant users in outdoor environments. Previous studies indicated that wind noise at the microphone/hearing aid output had high levels of low-frequency energy and the amount of noise generated is related to the microphone directionality. Currently, cochlear implants only offer either directional microphones or omnidirectional microphones for users at-large. As all cochlear implants utilize pre-emphasis filters to reduce low-frequency energy before the signal is encoded, effective wind noise reduction algorithms for hearing aids might not be applicable for cochlear implants. The purposes of this study were to investigate the effect of microphone directionality on speech recognition and perceived sound quality of cochlear implant users in wind noise and to derive effective wind noise reduction strategies for cochlear implants. A repeated-measure design was used to examine the effects of spectral and temporal masking created by wind noise recorded through directional and omnidirectional microphones and the effects of pre-emphasis filters on cochlear implant performance. A digital hearing aid was programmed to have linear amplification and relatively flat in-situ frequency responses for the directional and omnidirectional modes. The hearing aid output was then recorded from 0 to 360° at flow velocities of 4.5 and 13.5 m/sec in a quiet wind tunnel. Sixteen postlingually deafened adult cochlear implant listeners who reported to be able to communicate on the phone with friends and family without text messages participated in the study. Cochlear implant users listened to speech in wind noise recorded at locations that the directional and omnidirectional microphones yielded the lowest noise levels. Cochlear implant listeners repeated the sentences and rated the sound quality of the testing materials. Spectral and temporal characteristics of flow noise, as well as speech and/or noise characteristics before

Investigating properties of white noise in the undergraduate laboratory

Energy Technology Data Exchange (ETDEWEB)

Hassan, Umer; Shamim, Sohaib; Anwar, M Sabieh [School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore 54792 (Pakistan)], E-mail: umersiddiqui@lums.edu.pk, E-mail: sohaibshamim@lums.edu.pk, E-mail: sabieh@lums.edu.pk

2009-09-15

This paper describes a simple noise circuit for the undergraduate physics laboratory. Students use this circuit to study the properties of electrical noise on a personal computer. This is made possible by using a data acquisition system that allows the experimenters to obtain large amounts of data on the computer, suitable for subsequent mathematical computations. Various properties such as mean, noise power, noise power density and the probability distribution of noise voltages are also explored.

Noise suppression by noise

OpenAIRE

Vilar, J. M. G. (José M. G.), 1972-; Rubí Capaceti, José Miguel

2001-01-01

We have analyzed the interplay between an externally added noise and the intrinsic noise of systems that relax fast towards a stationary state, and found that increasing the intensity of the external noise can reduce the total noise of the system. We have established a general criterion for the appearance of this phenomenon and discussed two examples in detail.

[Exposure of schoolchildren and teachers to noise at school].

Science.gov (United States)

Koszarny, Z; Goryński, P

1990-01-01

The factor of decisive influence on the acoustic climate in rooms is the inner noise, which is dependent in schools on the activity of children, overcrowding of classes and inadequate use of technical protective means. The inappropriate location of schools, although also important from the standpoint of acoustics, is a much lower source of noise than it is generally assumed. Particularly unfavourable acoustic conditions are in elementary schools with over 300 children in one shift. The spaces with the highest noise level include corridors, especially during recesses between lessons. The noise level in them is in the range of an equivalent sound A 60-95 dB, and the most frequent noise level is 80 dB. In a large part of schools the acoustic conditions in the corridors during recesses approach the critical values accepted for hearing protection in industrial plants, in some schools they are even exceeded. The situation is also unfavourable in other rooms such as doctor's office, director's room, reading rooms, rooms for teachers. These rooms are situated usually without taking into consideration of the acoustic conditions. This is particularly true of teachers' rooms which should give the teachers the possibility of resting before the next lesson. During lessons the noise level decreases in all rooms. However, the noisiest among them, corridors, classes situated near the hall for physical exercises and day-room, have still up to about 65 dB noise level. Generally speaking, in about 60% of rooms the acoustic conditions are below the recommended standard. The main cause, apart from overcrowding of schools, is low acoustic absorption ability of school rooms, and poor acoustic insulation ability of the doors in schools.

Aircraft noise in the region of the Bucharest-Otopeni Airport. [noise pollution in airport environment

Science.gov (United States)

Costescu, M.; Gherghel, C.; Curtoglu, A.

1974-01-01

Aircraft noise, especially in the region adjoining airports, constitutes a problem that will be aggravated in the near future because of increasing aircraft traffic and the appearance of new types of large tonnage aircraft with continuously increasing powers and speeds. Criteria for the evaluation of aircraft noise are reported and some results of studies carried out in the region of Bucharest-Otopeni Airport are detailed.

Noise Annoyance in Urban Children: A Cross-Sectional Population-Based Study

Science.gov (United States)

Grelat, Natacha; Houot, Hélène; Pujol, Sophie; Levain, Jean-Pierre; Defrance, Jérôme; Mariet, Anne-Sophie; Mauny, Frédéric

2016-01-01

Acoustical and non-acoustical factors influencing noise annoyance in adults have been well-documented in recent years; however, similar knowledge is lacking in children. The aim of this study was to quantify the annoyance caused by chronic ambient noise at home in children and to assess the relationship between these children′s noise annoyance level and individual and contextual factors in the surrounding urban area. A cross sectional population-based study was conducted including 517 children attending primary school in a European city. Noise annoyance was measured using a self-report questionnaire adapted for children. Six noise exposure level indicators were built at different locations at increasing distances from the child′s bedroom window using a validated strategic noise map. Multilevel logistic models were constructed to investigate factors associated with noise annoyance in children. Noise indicators in front of the child′s bedroom (p ≤ 0.01), family residential satisfaction (p ≤ 0.03) and socioeconomic characteristics of the individuals and their neighbourhood (p ≤ 0.05) remained associated with child annoyance. These findings illustrate the complex relationships between our environment, how we may perceive it, social factors and health. Better understanding of these relationships will undoubtedly allow us to more effectively quantify the actual effect of noise on human health. PMID:27801858

Influence of Personal Factors on Sound Perception and Overall Experience in Urban Green Areas. A Case Study of a Cycling Path Highly Exposed to Road Traffic Noise

Directory of Open Access Journals (Sweden)

Francesco Aletta

2018-05-01

Full Text Available In contemporary urban design, green public areas play a vital role. They have great societal value, but if exposed to undue environmental noise their restorative potential might be compromised. On the other hand, research has shown that the presence of greenery can moderate noise annoyance in areas with high sound levels, while personal factors are expected to play an important role too. A cycling path bordered by vegetation, but highly exposed to road traffic noise, was here considered as a case study. A sound perception survey was submitted to participants on site and they were subsequently sorted into groups according to their noise sensitivity, visual attention and attitude towards greenery. The aim of this study was testing whether these three personal factors could affect their noise perception and overall experience of the place. Results showed that people highly sensitive to noise and more sceptical towards greenery’s potential as an environmental moderator reported worse soundscape quality, while visually attentive people reported better quality. These three personal factors were found to be statistically independent. This study shows that several person-related factors impact the assessment of the sound environment in green areas. Although the majority of the respondents benefit from the presence of visual green, policy-makers and planners should be aware that for a significant subset of the population, it should be accompanied by a tranquil soundscape to be fully appreciated.

AIRPORT NOISE CHARGES AND LOCAL COMMUNITIES: APPLICATION TO REGIONAL AIRPORTS

Directory of Open Access Journals (Sweden)

LUCA MANTECCHINI

2016-11-01

Full Text Available There have always been conflicts among airports and local communities due to the aeronautical noise generated by airport operations. In fact, this is a factor that - if not properly managed - could severely cut down the growth of air traffic in an airport with direct effects on the economic and territorial system. Beside this, in the last decade the critical issues related to the impact of aeronautical noise on airport operations have greatly reduced, thanks to technological improvements in aircraft design. Nevertheless, the reduction of noise emissions during a single aircraft operation does not make the issue of the airports’ location less important. This is the case of regional airports in EU, which have recently experimented a large traffic increase due to the development of low-cost traffic. It is now clear that the problem cannot be reduced to its mere technological aspect, but it ought to be dealt with the involvement of the various stakeholders in order to mitigate the emissions and adequately compensate the impacts to local communities. Typically, there are two possible countermeasures to mitigate the effects of aircraft noise: operational measures, based on the application of technological and organizational devices and market-based measures. The application of noise taxes, aiming at compensating the negative externalities generated by airport operations is becoming increasingly widespread in EU. In this paper, a methodology for the application of noise taxes based on the actual noise of aircraft operating into an airport is discussed and implemented in a test case.

The Contribution of Auditory and Cognitive Factors to Intelligibility of Words and Sentences in Noise.

Science.gov (United States)

Heinrich, Antje; Knight, Sarah

2016-01-01

Understanding the causes for speech-in-noise (SiN) perception difficulties is complex, and is made even more difficult by the fact that listening situations can vary widely in target and background sounds. While there is general agreement that both auditory and cognitive factors are important, their exact relationship to SiN perception across various listening situations remains unclear. This study manipulated the characteristics of the listening situation in two ways: first, target stimuli were either isolated words, or words heard in the context of low- (LP) and high-predictability (HP) sentences; second, the background sound, speech-modulated noise, was presented at two signal-to-noise ratios. Speech intelligibility was measured for 30 older listeners (aged 62-84) with age-normal hearing and related to individual differences in cognition (working memory, inhibition and linguistic skills) and hearing (PTA(0.25-8 kHz) and temporal processing). The results showed that while the effect of hearing thresholds on intelligibility was rather uniform, the influence of cognitive abilities was more specific to a certain listening situation. By revealing a complex picture of relationships between intelligibility and cognition, these results may help us understand some of the inconsistencies in the literature as regards cognitive contributions to speech perception.

Assessment of Traffic Noise Impacts

DEFF Research Database (Denmark)

Rich, Jeppe Husted; Nielsen, Otto Anker

2004-01-01

A steady growth in traffic intensities in most urban areas throughout the world has forced planners and politicians to seriously consider the resulting environmental impact, such as traffic noise, accidents and air pollution. The assessment of such negative factors is needed in order to reveal...... the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...

Noise reduction with complex bilateral filter.

Science.gov (United States)

Matsumoto, Mitsuharu

2017-12-01

This study introduces a noise reduction technique that uses a complex bilateral filter. A bilateral filter is a nonlinear filter originally developed for images that can reduce noise while preserving edge information. It is an attractive filter and has been used in many applications in image processing. When it is applied to an acoustical signal, small-amplitude noise is reduced while the speech signal is preserved. However, a bilateral filter cannot handle noise with relatively large amplitudes owing to its innate characteristics. In this study, the noisy signal is transformed into the time-frequency domain and the filter is improved to handle complex spectra. The high-amplitude noise is reduced in the time-frequency domain via the proposed filter. The features and the potential of the proposed filter are also confirmed through experiments.

WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Adverse Birth Outcomes.

Science.gov (United States)

Nieuwenhuijsen, Mark J; Ristovska, Gordana; Dadvand, Payam

2017-10-19

not conduct meta-analyses. Discussion: This systematic review is supported by previous systematic reviews and meta-analyses that suggested that there may be some suggestive evidence for an association between environmental noise exposure and birth outcomes, although they pointed more generally to a stronger role of occupational noise exposure, which tends to be higher and last longer. Very strict criteria for inclusion and exclusion of studies, performance of quality assessment for risk of bias, and finally applying GRADE principles for judgment of quality of evidence are the strengths of this review. We found evidence of very low quality for associations between aircraft noise and preterm birth, low birth weight and congenital anomalies, and low quality evidence for an association between road traffic noise and low birth weight, preterm birth and small for gestational age. Further high quality studies are required to establish such associations. Future studies are recommended to apply robust exposure assessment methods (e.g., modeled or measured noise levels at bedroom façade), disentangle associations for different sources of noise as well as daytime and nighttime noise, evaluate the impacts of noise evens (that stand out of the noise background), and control the analyses for confounding factors, such as socioeconomic status, lifestyle factors and other environmental factors, especially air pollution.

WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Adverse Birth Outcomes

Directory of Open Access Journals (Sweden)

Mark J. Nieuwenhuijsen

2017-10-01

studies, we did not conduct meta-analyses. Discussion: This systematic review is supported by previous systematic reviews and meta-analyses that suggested that there may be some suggestive evidence for an association between environmental noise exposure and birth outcomes, although they pointed more generally to a stronger role of occupational noise exposure, which tends to be higher and last longer. Very strict criteria for inclusion and exclusion of studies, performance of quality assessment for risk of bias, and finally applying GRADE principles for judgment of quality of evidence are the strengths of this review. Conclusions: We found evidence of very low quality for associations between aircraft noise and preterm birth, low birth weight and congenital anomalies, and low quality evidence for an association between road traffic noise and low birth weight, preterm birth and small for gestational age. Further high quality studies are required to establish such associations. Future studies are recommended to apply robust exposure assessment methods (e.g., modeled or measured noise levels at bedroom façade, disentangle associations for different sources of noise as well as daytime and nighttime noise, evaluate the impacts of noise evens (that stand out of the noise background, and control the analyses for confounding factors, such as socioeconomic status, lifestyle factors and other environmental factors, especially air pollution.

Noise performance of frequency modulation Kelvin force microscopy

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Heinrich Diesinger

2014-01-01

Full Text Available Noise performance of a phase-locked loop (PLL based frequency modulation Kelvin force microscope (FM-KFM is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values.

[Occupational noise exposure and work accidents].

Science.gov (United States)

Dias, Adriano; Cordeiro, Ricardo; Gonçalves, Cláudia Giglio de Oliveira

2006-10-01

The purpose of this study was to verify whether occupational noise exposure is a significant risk factor for work accidents in the city of Piracicaba, São Paulo State, Brazil. This hospital-based case-control study included 600 workers aged 15-60 who suffered typical occupational accidents between May and October 2004 and were seen at the Piracicaba Orthopedics and Trauma Center. The control group comprised 822 workers, aged 15-60, who were also seen at the Center, and either had a non-occupational accident or were accompanying someone who had suffered an accident. A multiple logistic regression model was adjusted with work accident as an independent variable, controlled by covariables of interest such as noise exposure. The risk of having a work accident was about twice as high among workers exposed to noise, after controlling for several covariables. Occupational noise exposure not only affected auditory health status but was also a risk factor for work accidents.

Noise characteristics of barium ferrite particulate rigid disks

Science.gov (United States)

Kodama, Naoki; Inoue, Hitoshi; Spratt, Geoffrey; Uesaka, Yasutaro; Katsumoto, Masayuki

1991-04-01

This paper discusses the relationship between the noise characteristics and magnetic properties of longitudinal barium ferrite (Ba-F) rigid disks with different switching field distributions (SFD). The magnetomotive force dependencies of reverse dc-erase (RDC) noise are measured and compared with SFD values. Coated disks with acicular magnetic particles have dips and thin-film disks peaks in the RDC. In Ba-F disks, both cases are observed depending on the SFD values, though the depths or heights of the RDC noise are much smaller than those of coated disks with acicular particles or thin-film disks. Disks with small SFD values have peaks, and disks with large SFD values have dips. In order to find the relationship between noise properties and magnetic properties, interparticle interactions in Ba-F disks are investigated. Reverse dc remanence Id(H) and ac-demagnetized isothermal remanence Ir(H) are measured. Both are normalized by the saturation remanence. The deviation from the noninteracting system, ΔM = Id(H) - [1ΔM=Id(H)-[1- 2Ir(H)] and an interaction field factor (IFF) given by (H'r - Hr)/Hc, are derived from these remanent properties. Here, H'r is the field corresponding to 50% of the remanent magnetization, Hr is remanence coercivity. In Ba-F disks, ΔM shows positive interactions, and the peak heights of ΔM increase and IFF decrease with decreasing SFD values. Positive interactions between Ba-F particles seem to be caused by particle stacking. Therefore, particle stacking results in small SFD values and peak-type RDC noise.

Analytical models of probability distribution and excess noise factor of solid state photomultiplier signals with crosstalk

International Nuclear Information System (INIS)

Vinogradov, S.

2012-01-01

Silicon Photomultipliers (SiPM), also called Solid State Photomultipliers (SSPM), are based on Geiger mode avalanche breakdown that is limited by a strong negative feedback. An SSPM can detect and resolve single photons due to the high gain and ultra-low excess noise of avalanche multiplication in this mode. Crosstalk and afterpulsing processes associated with the high gain introduce specific excess noise and deteriorate the photon number resolution of the SSPM. The probabilistic features of these processes are widely studied because of its significance for the SSPM design, characterization, optimization and application, but the process modeling is mostly based on Monte Carlo simulations and numerical methods. In this study, crosstalk is considered to be a branching Poisson process, and analytical models of probability distribution and excess noise factor (ENF) of SSPM signals based on the Borel distribution as an advance on the geometric distribution models are presented and discussed. The models are found to be in a good agreement with the experimental probability distributions for dark counts and a few photon spectrums in a wide range of fired pixels number as well as with observed super-linear behavior of crosstalk ENF.

On the Impact of Anomalous Noise Events on Road Traffic Noise Mapping in Urban and Suburban Environments.

Science.gov (United States)

Orga, Ferran; Alías, Francesc; Alsina-Pagès, Rosa Ma

2017-12-23

Noise pollution is a critical factor affecting public health, the relationship between road traffic noise (RTN) and several diseases in urban areas being especially disturbing. The Environmental Noise Directive 2002/49/EC and the CNOSSOS-EU framework are the main instruments of the European Union to identify and combat noise pollution, requiring Member States to compose and publish noise maps and noise management action plans every five years. Nowadays, the noise maps are starting to be tailored by means of Wireless Acoustic Sensor Networks (WASN). In order to exclusively monitor the impact of RTN on the well-being of citizens through WASN-based approaches, those noise sources unrelated to RTN denoted as Anomalous Noise Events (ANEs) should be removed from the noise map generation. This paper introduces an analysis methodology considering both Signal-to-Noise Ratio (SNR) and duration of ANEs to evaluate their impact on the A-weighted equivalent RTN level calculation for different integration times. The experiments conducted on 9 h of real-life data from the WASN-based DYNAMAP project show that both individual high-impact events and aggregated medium-impact events bias significantly the equivalent noise levels of the RTN map, making any derived study about public health impact inaccurate.

Voltage fluctuations in neurons: signal or noise?

DEFF Research Database (Denmark)

Yarom, Yosef; Hounsgaard, Jorn

2011-01-01

, we discuss noise-free neuronal signaling and detrimental and beneficial forms of noise in large-scale functional neural networks. Evidence that noise and variability in some cases go hand in hand with behavioral variability and increase behavioral choice, richness, and adaptability opens new avenues......Noise and variability are fundamental companions to ion channels and synapses and thus inescapable elements of brain function. The overriding unresolved issue is to what extent noise distorts and limits signaling on one hand and at the same time constitutes a crucial and fundamental enrichment...... that allows and facilitates complex adaptive behavior in an unpredictable world. Here we review the growing experimental evidence that functional network activity is associated with intense fluctuations in membrane potential and spike timing. We trace origins and consequences of noise and variability. Finally...

Preschool Personnel Exposure to Occupational Noise

Directory of Open Access Journals (Sweden)

Kaļužnaja Darja

2016-10-01

Full Text Available Increased noise, which is also below the occupational exposure values and is “hearing safe” noise, affects the exposed person’s health as a non-specific stressor. Increased noise level also creates an environment for additional vocal apparatus load. The objective of this study was to determine preschool personnel occupational noise and its relationship with subjective health complaints. Data were obtained with survey assistance through subjective answers of respondents about health complaints and noise exposure among Rīga preschool personnel. Objective noise measurements were made to assess real noise levels in the preschool environment. Data from 155 respondents and objective measurements of 37 preschool classrooms were obtained. The results showed that the average 8-h noise exposure among Rīga preschool educational institutions was 70 dB(A, which did not exceed the Latvian work environment noise limits, but exceeded the 35–40 dB(A noise limit in the educational environment guidelines recommended by the WHO. The survey results showed that loud noise is one of the most important workplace environmental factors (~70% of respondents feel a necessity to increase voice because of noise. A constant feeling of fatigue, headache, irritable feeling, and a desire to isolate oneself from others more often occurred in respondents exposed to increased noise, compared with those who noted that they were not exposed to increased noise. In general, loud noise was associated with increased subjective health complaints in preschool education institution personnel.

Post commissioning noise study

International Nuclear Information System (INIS)

Heraud, P.

2008-01-01

This presentation described a wind farm post-commissioning study conducted at a wind farm owned by Helimax Energy Inc. The farm was located in a partly-forested, partly cultivated region in Quebec that featured gently rolling hills. Over 600 dwellings were located within 2 km of the wind farm, and 44 dwellings were within the wind farm's boundaries. The noise impact assessments were conducted at various points near the wind farm. The wind farm was designed using an International Standards Organization (ISO) noise propagation model and a 40 dBA to provide adequate setbacks. The study was conducted using 10 days of continuous measurements at selected points of a wind farm. Points of reception included points from 650 m to 800 m. Noise over 2 km was not thought to be contributed by the wind turbine. The nearest dwelling was 512 m from one of the farm's wind turbines. The study also considered ground factor, temperature, relative humidity, and the height of the receptors. Quebec noise level limits are 40 dBA at night, and 45 dBA during the day. Noise level limits are independent of wind speed. Measured noise contributions over 40 dBA were not observed during the measurement program. The wind turbines were only audible for 1 night out of the 30 night study period. It was concluded that the ISO noise propagation model is a reliable tool for conducting noise impact assessments. tabs., figs

Physiologic correlates to background noise acceptance

Science.gov (United States)

Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

2004-05-01

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

Instrument Variables for Reducing Noise in Parallel MRI Reconstruction

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Yuchou Chang

2017-01-01

Full Text Available Generalized autocalibrating partially parallel acquisition (GRAPPA has been a widely used parallel MRI technique. However, noise deteriorates the reconstructed image when reduction factor increases or even at low reduction factor for some noisy datasets. Noise, initially generated from scanner, propagates noise-related errors during fitting and interpolation procedures of GRAPPA to distort the final reconstructed image quality. The basic idea we proposed to improve GRAPPA is to remove noise from a system identification perspective. In this paper, we first analyze the GRAPPA noise problem from a noisy input-output system perspective; then, a new framework based on errors-in-variables (EIV model is developed for analyzing noise generation mechanism in GRAPPA and designing a concrete method—instrument variables (IV GRAPPA to remove noise. The proposed EIV framework provides possibilities that noiseless GRAPPA reconstruction could be achieved by existing methods that solve EIV problem other than IV method. Experimental results show that the proposed reconstruction algorithm can better remove the noise compared to the conventional GRAPPA, as validated with both of phantom and in vivo brain data.

Effects of occupational noise exposure on changes in blood pressure of workers

Directory of Open Access Journals (Sweden)

Hossein Ali Yousefi Rizi

2013-01-01

Full Text Available    BACKGROUND: In most industries, workers are exposed to loud noise. Noise is considered as a nonspecific biological stressor that have adverse effects on human physiology. It is associated with hypertension which is in turn one of the most important preventable risk factors of cardiovascular disorders. This study aimed to evaluate the effects of noise on changes of workers' blood pressure.    METHODS: This cross-sectional study was performed on 90 individuals who were exposed to noise at one of the industries in Isfahan, Iran. Noise levels (in dBA were measured by means of a sound level meter. Data was collected using a demographic questionnaire and physical examination. Blood pressure was measured by a sphygmomanometer at workplace. The collected data was analyzed by t-tests.    RESULTS: The workers aged 31.5 ± 5.2 years and were exposed to mean noise level of 97.5 ± 10.1 dBA which was significantly above the standard level (85 dBA.The relationships between blood pressure, heart rate, and noise level were not significant. However, Pearson’s correlation indicated systolic blood pressure to have significant correlations with age (correlation coefficient = 0.302 and work experience (correlation coefficient = 0.299.    CONCLUSION: Workers exposed to noise levels above the standard, especially in the metal industry but their blood pressures haven’t any associated with noise. it mention that any changes in blood pressure resulting from occupational noise are likely to be small, careful controls, large sample sizes, and long time exposure to noise would be take to identify significant effects.       Keywords: Noise Exposure, Blood Pressure, Young Workers, Cardiovascular Disease, Metal Industries

Identification of noise in linear data sets by factor analysis

International Nuclear Information System (INIS)

Roscoe, B.A.; Hopke, Ph.K.

1982-01-01

A technique which has the ability to identify bad data points, after the data has been generated, is classical factor analysis. The ability of classical factor analysis to identify two different types of data errors make it ideally suited for scanning large data sets. Since the results yielded by factor analysis indicate correlations between parameters, one must know something about the nature of the data set and the analytical techniques used to obtain it to confidentially isolate errors. (author)

The recommendations of the noise working group

International Nuclear Information System (INIS)

Legerton, M.L.

1997-01-01

In 1993 the DTI set up a Working Group to define a framework which can be used to measure and rate the noise from wind turbines. The final report of the Noise Working Group is now available for publication. The advice on the setting of noise limits for wind farms is largely unaltered from the preliminary recommendations presented at the 17th BWEA Annual Conference [1]. This paper recaps on those recommendations and provides additional information on the measurement procedures to be used with the recommendations on noise limits. The paper describes the measurement of the existing background noise climate on which the limits are based and the procedure to be used for the measurement of turbine noise levels in the investigation of complaints. The noise limits are rated noise levels in that they can include a penalty for tones present in the noise. The level of penalty depends upon the audibility of the tone and measurement procedure for determining audibility and the associated penalty system are also described. (author)

Large signal-to-noise ratio quantification in MLE for ARARMAX models

Science.gov (United States)

Zou, Yiqun; Tang, Xiafei

2014-06-01

It has been shown that closed-loop linear system identification by indirect method can be generally transferred to open-loop ARARMAX (AutoRegressive AutoRegressive Moving Average with eXogenous input) estimation. For such models, the gradient-related optimisation with large enough signal-to-noise ratio (SNR) can avoid the potential local convergence in maximum likelihood estimation. To ease the application of this condition, the threshold SNR needs to be quantified. In this paper, we build the amplitude coefficient which is an equivalence to the SNR and prove the finiteness of the threshold amplitude coefficient within the stability region. The quantification of threshold is achieved by the minimisation of an elaborately designed multi-variable cost function which unifies all the restrictions on the amplitude coefficient. The corresponding algorithm based on two sets of physically realisable system input-output data details the minimisation and also points out how to use the gradient-related method to estimate ARARMAX parameters when local minimum is present as the SNR is small. Then, the algorithm is tested on a theoretical AutoRegressive Moving Average with eXogenous input model for the derivation of the threshold and a gas turbine engine real system for model identification, respectively. Finally, the graphical validation of threshold on a two-dimensional plot is discussed.

Quantum dynamics of a Josephson junction driven cavity mode system in the presence of voltage bias noise

Science.gov (United States)

Wang, Hui; Blencowe, M. P.; Armour, A. D.; Rimberg, A. J.

2017-09-01

We give a semiclassical analysis of the average photon number as well as photon number variance (Fano factor F ) for a Josephson junction (JJ) embedded microwave cavity system, where the JJ is subject to a fluctuating (i.e., noisy) bias voltage with finite dc average. Through the ac Josephson effect, the dc voltage bias drives the effectively nonlinear microwave cavity mode into an amplitude squeezed state (F Armour et al., Phys. Rev. Lett. 111, 247001 (2013), 10.1103/PhysRevLett.111.247001], but bias noise acts to degrade this squeezing. We find that the sensitivity of the Fano factor to bias voltage noise depends qualitatively on which stable fixed point regime the system is in for the corresponding classical nonlinear steady-state dynamics. Furthermore, we show that the impact of voltage bias noise is most significant when the cavity is excited to states with large average photon number.

Environmental noise forecasting based on support vector machine

Science.gov (United States)

Fu, Yumei; Zan, Xinwu; Chen, Tianyi; Xiang, Shihan

2018-01-01

As an important pollution source, the noise pollution is always the researcher's focus. Especially in recent years, the noise pollution is seriously harmful to the human beings' environment, so the research about the noise pollution is a very hot spot. Some noise monitoring technologies and monitoring systems are applied in the environmental noise test, measurement and evaluation. But, the research about the environmental noise forecasting is weak. In this paper, a real-time environmental noise monitoring system is introduced briefly. This monitoring system is working in Mianyang City, Sichuan Province. It is monitoring and collecting the environmental noise about more than 20 enterprises in this district. Based on the large amount of noise data, the noise forecasting by the Support Vector Machine (SVM) is studied in detail. Compared with the time series forecasting model and the artificial neural network forecasting model, the SVM forecasting model has some advantages such as the smaller data size, the higher precision and stability. The noise forecasting results based on the SVM can provide the important and accuracy reference to the prevention and control of the environmental noise.

Shot noise of a quantum shuttle

DEFF Research Database (Denmark)

Novotny, Tomas; Donarini, Andrea; Flindt, Christian

2004-01-01

We formulate a theory for shot noise in quantum nanoelectromechanical systems. As a specific example, the theory is applied to a quantum shuttle, and the zero-frequency noise, measured by the Fano factor F, is computed. F reaches very low values (Fsimilar or equal to10(-2)) in the shuttling regim...

Combination therapy using antioxidants and low level laser therapy (LLLT) on noise induced hearing loss (NIHL)

Science.gov (United States)

Chang, So-Young; Lim, Sung Kyu; Lee, Min young; Chung, Phil-Sang; Jung, Jae-Yun; Rhee, Chung-Ku

2016-02-01

One of the most common factors that cause hearing disorders is noise trauma. Noise is an increasing hazard and it is pervasive, which makes it difficult to take precautions and prevent noise-induced hearing loss (NIHL). The prevalence of hearing loss among factory workers to be 42 %[1]. Ocupational noise induced hearing loss (ONIHL) continues to be a significant occupational hazard. ONIHL is permanent and may cause significant disability, for which there currently exists no cure, but is largely preventable. More than 30 million Americans are potentially exposed to hazardous noise levels in occupations such as transportation, construction, and coal mining, as well as recreationally. In the mainstream setting, exposure avoidance strategies aimed to reduce the incidence of ONIHL remain the focus of public health and occupational medicine approaches[2]. In military conditions this is most often caused by such things as explosions, blasts, or loud noises from vehicles ranging from 100 to 140 dB[3] and military weapons generating approximately 140-185 dB peak sound pressure levels[4].

Effect of Correlated Noises in a Genetic Model

International Nuclear Information System (INIS)

Li, Zhang; Li, Cao

2010-01-01

The Stratonovich stochastic differential equation is used to analyze genotype selection in the presence of correlated Gaussian white noises. We study the steady state properties of the genotype selection and discuss the effects of the correlated noises. It is found that the degree of correlation of the noises can be used to select one type of genes from another type of mixing genes. The strong selection of genes caused by a large value of multiplicative noise intensity can be weakened by the intensive negative correlation. (general)

Longitudinal changes in hearing threshold levels of noise-exposed construction workers

NARCIS (Netherlands)

Leensen, Monique C. J.; Dreschler, Wouter A.

2015-01-01

Longitudinal analysis of audiometric data of a large population of noise-exposed workers provides insight into the development of noise-induced hearing loss (NIHL) as a function of noise exposure and age, particularly during the first decade of noise exposure. Data of pure-tone audiometry of 17,930

The Contribution of Cognitive Factors to Individual Differences in Understanding Noise-Vocoded Speech in Young and Older Adults

Directory of Open Access Journals (Sweden)

Stephanie Rosemann

2017-06-01

Full Text Available Noise-vocoded speech is commonly used to simulate the sensation after cochlear implantation as it consists of spectrally degraded speech. High individual variability exists in learning to understand both noise-vocoded speech and speech perceived through a cochlear implant (CI. This variability is partly ascribed to differing cognitive abilities like working memory, verbal skills or attention. Although clinically highly relevant, up to now, no consensus has been achieved about which cognitive factors exactly predict the intelligibility of speech in noise-vocoded situations in healthy subjects or in patients after cochlear implantation. We aimed to establish a test battery that can be used to predict speech understanding in patients prior to receiving a CI. Young and old healthy listeners completed a noise-vocoded speech test in addition to cognitive tests tapping on verbal memory, working memory, lexicon and retrieval skills as well as cognitive flexibility and attention. Partial-least-squares analysis revealed that six variables were important to significantly predict vocoded-speech performance. These were the ability to perceive visually degraded speech tested by the Text Reception Threshold, vocabulary size assessed with the Multiple Choice Word Test, working memory gauged with the Operation Span Test, verbal learning and recall of the Verbal Learning and Retention Test and task switching abilities tested by the Comprehensive Trail-Making Test. Thus, these cognitive abilities explain individual differences in noise-vocoded speech understanding and should be considered when aiming to predict hearing-aid outcome.

Does noise from wind turbines change due to age?

International Nuclear Information System (INIS)

Andersen, B.; Jakobsen, J.

1995-06-01

It has been discussed whether the noise from a wind turbine increases due to wear of the mechanical parts or to pollution of the rotor blades. If this is so it should be taken into consideration at the design stage. The noise from wind turbines that had been measured several years before was measured again, and results were compared. A number of modifications of the same wind turbine was made throughout a period of two years during which noise was measured several times. No evidence that noise increases in accordance with the age of the windmill was found. A 75 kW wind turbine seems to have an unchanged A-weighted source strength L WA after a period of 6 years. The level of the tones in the noise from the large generator engaged had increased slightly. The noise from operation of the small generator showed a pronounced increase of one tone (approximately 10 dB), while two other tones were largely unchanged. In the case of periodic measurements of the noise from a 300 kW wind turbine, the gearbox tone noise was found to change markedly, without any obvious pattern. The large, apparently random, fluctuations mask any tendency towards changes of the tone level with time. Repeated measurements of four identical 100 kW wind turbines, show a general tendency towards an increase of the A-weighted source strength (L WA ). The increase of L WA between 1 and 2.7 dB, was found mainly in the frequency range 800 Hz to 3 kHz. The level of the third octave band, which includes a weak gearbox tone (315 Hz), seemed unchanged. Other measurements indicate a constant level of noise during the first three years of operation. (AB)

Nodule detection in digital chest radiography: Part of image background acting as pure noise

International Nuclear Information System (INIS)

Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Bochud, F. O.; Verdun, F. R.; Maansson, L. G.

2005-01-01

There are several factors that influence the radiologist's ability to detect a specific structure/lesion in a radiograph. Three factors that are commonly known to be of major importance are the signal itself, the system noise and the projected anatomy. The aim of this study was to determine to what extent the image background acts as pure noise for the detection of subtle lung nodules in five different regions of the chest. A receiver operating characteristic (ROC) study with five observers was conducted on two different sets of images, clinical chest X-ray images and images with a similar power spectrum as the clinical images but with a random phase spectrum, resulting in an image background containing pure noise. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrasts were added to the images. As a measure of the part of the image background that acts as pure noise, the ratio between the contrast needed to obtain an area under the ROC curve of 0.80 in the clinical images to that in the random-phase images was used. The ratio ranged from 0.40 (in the lateral pulmonary regions) to 0.83 (in the hilar regions) indicating that there was a large difference between different regions regarding to what extent the image background acted as pure noise; and that in the hilar regions the image background almost completely acted as pure noise for the detection of 10 mm nodules. (authors)

Noise countermeasures for accelerator facilities as seen from earth

Energy Technology Data Exchange (ETDEWEB)

Yasumoto, Masaru [Tokyo Univ. (Japan). Research Center for Nuclear Science and Technology

1996-12-01

As seen from the viewpoint of noise countermeasures, the earth system for various experimental facilities is generally improper, for example independent earth method. It is considered that only by changing this to the earth system which is suitable to noise countermeasures, the antinoise property can be largely heightened. Also it is important to make earth system into that, to which the countermeasure technology suitable to the features of facilities is applied. The features of large accelerators and their building structures related to noise circulation are explained. As to the basic technology of the earth system that heightens antinoise property, induction shielding, the resistance-dependent and inductance-dependent zones in its frequency characteristics, the lowering of impedance, the shielding characteristics of various cables, the method of realizing low impedance, the method of absorbing same phase noise, the characteristics of superhigh permeability materials, and the restraint of interference noise voltage by reducing common impedance and restraining circulating noise current are discussed. As the concrete countermeasures, the earth system in accelerator buildings and beam lines are shown. (K.I.)

Noise countermeasures for accelerator facilities as seen from earth

International Nuclear Information System (INIS)

Yasumoto, Masaru

1996-01-01

As seen from the viewpoint of noise countermeasures, the earth system for various experimental facilities is generally improper, for example independent earth method. It is considered that only by changing this to the earth system which is suitable to noise countermeasures, the antinoise property can be largely heightened. Also it is important to make earth system into that, to which the countermeasure technology suitable to the features of facilities is applied. The features of large accelerators and their building structures related to noise circulation are explained. As to the basic technology of the earth system that heightens antinoise property, induction shielding, the resistance-dependent and inductance-dependent zones in its frequency characteristics, the lowering of impedance, the shielding characteristics of various cables, the method of realizing low impedance, the method of absorbing same phase noise, the characteristics of superhigh permeability materials, and the restraint of interference noise voltage by reducing common impedance and restraining circulating noise current are discussed. As the concrete countermeasures, the earth system in accelerator buildings and beam lines are shown. (K.I.)

SELECTED PROBLEMS OF PROTECTION AGAINST ROAD TRAFFIC NOISE

Directory of Open Access Journals (Sweden)

Władysław Gardziejczyk

2015-11-01

Full Text Available The paper presents factors for assessment of road traffic noise level and possible actions towards the minimization of excessive noise in the roadway neighborhood. Changes of equivalent sound level values were analyzed in relation to traffic intensity, categorization and vehicles speed. In relation to measures reducing noise level in roadway’s surroundings particular attention was given to anti-noise protections and tyre/noise reduction. Acoustic effectiveness of specific solutions was showed based on chosen examples. It was proved that when admissible noise level is slightly exceeded the need for noise barrier use may be replaced by a proper design and maintenance of road pavement or by enforcement of speed limit.

Functional roles for noise in genetic circuits.

Science.gov (United States)

Eldar, Avigdor; Elowitz, Michael B

2010-09-09

The genetic circuits that regulate cellular functions are subject to stochastic fluctuations, or 'noise', in the levels of their components. Noise, far from just a nuisance, has begun to be appreciated for its essential role in key cellular activities. Noise functions in both microbial and eukaryotic cells, in multicellular development, and in evolution. It enables coordination of gene expression across large regulons, as well as probabilistic differentiation strategies that function across cell populations. At the longest timescales, noise may facilitate evolutionary transitions. Here we review examples and emerging principles that connect noise, the architecture of the gene circuits in which it is present, and the biological functions it enables. We further indicate some of the important challenges and opportunities going forward.

Spatiotemporal noise covariance estimation from limited empirical magnetoencephalographic data

International Nuclear Information System (INIS)

Jun, Sung C; Plis, Sergey M; Ranken, Doug M; Schmidt, David M

2006-01-01

The performance of parametric magnetoencephalography (MEG) and electroencephalography (EEG) source localization approaches can be degraded by the use of poor background noise covariance estimates. In general, estimation of the noise covariance for spatiotemporal analysis is difficult mainly due to the limited noise information available. Furthermore, its estimation requires a large amount of storage and a one-time but very large (and sometimes intractable) calculation or its inverse. To overcome these difficulties, noise covariance models consisting of one pair or a sum of multi-pairs of Kronecker products of spatial covariance and temporal covariance have been proposed. However, these approaches cannot be applied when the noise information is very limited, i.e., the amount of noise information is less than the degrees of freedom of the noise covariance models. A common example of this is when only averaged noise data are available for a limited prestimulus region (typically at most a few hundred milliseconds duration). For such cases, a diagonal spatiotemporal noise covariance model consisting of sensor variances with no spatial or temporal correlation has been the common choice for spatiotemporal analysis. In this work, we propose a different noise covariance model which consists of diagonal spatial noise covariance and Toeplitz temporal noise covariance. It can easily be estimated from limited noise information, and no time-consuming optimization and data-processing are required. Thus, it can be used as an alternative choice when one-pair or multi-pair noise covariance models cannot be estimated due to lack of noise information. To verify its capability we used Bayesian inference dipole analysis and a number of simulated and empirical datasets. We compared this covariance model with other existing covariance models such as conventional diagonal covariance, one-pair and multi-pair noise covariance models, when noise information is sufficient to estimate them. We

Effect of external classroom noise on schoolchildren's reading and mathematics performance: correlation of noise levels and gender.

Science.gov (United States)

Papanikolaou, M; Skenteris, N; Piperakis, S M

2015-02-01

The present study investigated the effect of low, medium, and high traffic road noise as well as irrelevant background speech noise on primary school children's reading and mathematical performance. A total of 676 participants (324 boys, 47.9% and 352 girls, 52.1%) of the 4th and 5th elementary classes participated in the project. The participants were enrolled in public primary schools from urban areas and had ages ranging from 9 to 10 years and from. Schools were selected on the basis of increasing levels of exposure to road traffic noise and then classified into three categories (Low noise: 55-66 dB, Medium noise: 67-77 dB, and High noise: 72-80 dB). We measured reading comprehension and mathematical skills in accordance with the national guidelines for elementary education, using a test designed specifically for the purpose of this study. On the one hand, children in low-level noise schools showed statistically significant differences from children in medium- and high-level noise schools in reading performance (plevel noise schools differed significantly from children in high-level noise schools but only in mathematics performance (p=0.001). Girls in general did better in reading score than boys, especially in schools with medium- and high-level noise. Finally the levels of noise and gender were found to be two independent factors.

Noise-induced hearing loss: an occupational medicine perspective.

Science.gov (United States)

Stucken, Emily Z; Hong, Robert S

2014-10-01

Up to 30 million workers in the United States are exposed to potentially detrimental levels of noise. Although reliable medications for minimizing or reversing noise-induced hearing loss (NIHL) are not currently available, NIHL is entirely preventable. The purpose of this article is to review the epidemiology and pathophysiology of occupational NIHL. We will focus on at-risk populations and discuss prevention programs. Current prevention programs focus on reducing inner ear damage by minimizing environmental noise production and through the use of personal hearing protective devices. NIHL is the result of a complex interaction between environmental factors and patient factors, both genetic and acquired. The effects of noise exposure are specific to an individual. Trials are currently underway evaluating the role of antioxidants in protection from, and even reversal of, NIHL. Occupational NIHL is the most prevalent occupational disease in the United States. Occupational noise exposures may contribute to temporary or permanent threshold shifts, although even temporary threshold shifts may predispose an individual to eventual permanent hearing loss. Noise prevention programs are paramount in reducing hearing loss as a result of occupational exposures.

A simplified method of estimating noise power spectra

International Nuclear Information System (INIS)

Hanson, K.M.

1998-01-01

A technique to estimate the radial dependence of the noise power spectrum of images is proposed in which the calculations are conducted solely in the spatial domain of the noise image. The noise power spectrum averaged over a radial spatial-frequency interval is obtained form the variance of a noise image that has been convolved with a small kernel that approximates a Laplacian operator. Recursive consolidation of the image by factors of two in each dimension yields estimates of the noise power spectrum over that full range of spatial frequencies

Facial soft tissue thicknesses: Noise, signal, and P.

Science.gov (United States)

Stephan, Carl N; Munn, Lachlan; Caple, Jodi

2015-12-01

Facial soft tissue thicknesses (FSTTs) hold an important role in craniofacial identification, forming the underlying quantitative basis of craniofacial superimposition and facial approximation methods. It is, therefore, important that patterns in FSTTs be correctly described and interpreted. In prior FSTT literature, small statistically significant differences have almost universally been overemphasized and misinterpreted to reflect sex and ancestry effects when they instead largely encode nuisance statistical noise. Here we examine FSTT data and give an overview of why P-values do not mean everything. Scientific inference, not mechanical evaluation of P, should be awarded higher priority and should form the basis of FSTT analysis. This hinges upon tempered consideration of many factors in addition to P, e.g., study design, sampling, measurement errors, repeatability, reproducibility, and effect size. While there are multiple lessons to be had, the underlying message is foundational: know enough statistics to avoid misinterpreting background noise for real biological effects. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Maximizing signal-to-noise ratio (SNR) in 3-D large bandgap semiconductor pixelated detectors in optimal and non-optimal filtering conditions

International Nuclear Information System (INIS)

Rodrigues, Miesher L.; Serra, Andre da S.; He, Zhong; Zhu, Yuefeng

2009-01-01

3-D pixelated semiconductor detectors are used in radiation detection applications requiring spectroscopic and imaging information from radiation sources. Reconstruction algorithms used to determine direction and energy of incoming gamma rays can be improved by reducing electronic noise and using optimum filtering techniques. Position information can be improved by achieving sub-pixel resolution. Electronic noise is the limiting factor. Achieving sub-pixel resolution - position of the interaction better than one pixel pitch - in 3-D pixelated semiconductor detectors is a challenging task due to the fast transient characteristics of these signals. This work addresses two fundamental questions: the first is to determine the optimum filter, while the second is to estimate the achievable sub-pixel resolution using this filter. It is shown that the matched filter is the optimum filter when applying the signal-to-noise ratio criteria. Also, non-optimum filters are studied. The framework of 3-D waveform simulation using the Shockley-Ramo Theorem and the Hecht Equation for electron and hole trapping is presented in this work. This waveform simulator can be used to analyze current detectors as well as explore new ideas and concepts in future work. Numerical simulations show that assuming an electronic noise of 3.3 keV it is possible to subdivide the pixel region into 5x5 sub-pixels. After analyzing these results, it is suggested that sub-pixel information can also improve energy resolution. Current noise levels present the major drawback to both achieve sub-pixel resolution as well as improve energy resolution below the current limits. (author)

A descriptive study of noise in the neonatal intensive care unit: ambient levels and perceptions of contributing factors.

Science.gov (United States)

Darcy, Ashley E; Hancock, Lauren E; Ware, Emily J

2008-10-01

To examine the baseline acoustic environment in several mid-Atlantic region neonatal intensive care units (NICUs) and investigate the perceived factors contributing to noise levels in these NICUs. Quantitative data were collected from 3 urban, mid-Atlantic level IIIB and level IIIC NICUs. Qualitative data were collected via interview from 2 RNs employed in each of the study NICUs. This was an exploratory descriptive study utilizing a mixed-methods approach. A quantitative method was used for sound-level data collection, and a qualitative method was utilized during interviews with nurses to examine perceptions of factors contributing to noise. Ambient sound levels, measured in decibels, were taken at 5-minute intervals over a 2-hour period during both day and night shifts in a central location at each NICU. In addition, nurses were interviewed using a standardized interview questionnaire, and these interviews were then reviewed to determine themes regarding perceived factors contributing to sound levels. Hourly mean sound levels in each NICU ranged from 53.9 dB to 60.6 dB, with no statistically significant difference between noise levels recorded on day shift versus night shift, and no statistically significant difference among sites. Qualitative data showed that nurses' believed day shift to be louder than night shift and many perceived their own NICU as "pretty quiet." Key contributing factors to increased sound levels were stated as monitors or alarms, performing invasive procedures, presence of family, nurses or doctors giving report or rounds, and ringing phones. Noise levels were found to be above the American Academy of Pediatrics-recommended 45-dB level and often louder than the 50-dB level, which should not be exceeded more than 10% of the time. The recommended impulse maximum of 65 dB was also exceeded. Environmental Protection Agency recommendations for hospitals include sound levels no louder than 35 dB on night shift; this standard was also violated

A descriptive study of noise in the neonatal intensive care unit. Ambient levels and perceptions of contributing factors.

Science.gov (United States)

Darcy, Ashley E; Hancock, Lauren E; Ware, Emily J

2008-06-01

To examine the baseline acoustic environment in several mid-Atlantic region neonatal intensive care units (NICUs) and investigate the perceived factors contributing to noise levels in these NICUs. Quantitative data were collected from 3 urban, mid-Atlantic level IIIB and level IIIC NICUs. Qualitative data were collected via interview from 2 RNs employed in each of the study NICUs. This was an exploratory descriptive study utilizing a mixed-methods approach. A quantitative method was used for sound-level data collection, and a qualitative method was utilized during interviews with nurses to examine perceptions of factors contributing to noise. Ambient sound levels, measured in decibels, were taken at 5-minute intervals over a 2-hour period during both day and night shifts in a central location at each NICU. In addition, nurses were interviewed using a standardized interview questionnaire, and these interviews were then reviewed to determine themes regarding perceived factors contributing to sound levels. Hourly mean sound levels in each NICU ranged from 53.9 dB to 60.6 dB, with no statistically significant difference between noise levels recorded on day shift versus night shift, and no statistically significant difference among sites. Qualitative data showed that nurses' believed day shift to be louder than night shift and many perceived their own NICU as "pretty quiet." Key contributing factors to increased sound levels were stated as monitors or alarms, performing invasive procedures, presence of family, nurses or doctors giving report or rounds, and ringing phones. Noise levels were found to be above the American Academy of Pediatrics--recommended 45-dB level and often louder than the 50-dB level, which should not be exceeded more than 10% of the time. The recommended impulse maximum of 65 dB was also exceeded. Environmental Protection Agency recommendations for hospitals include sound levels no louder than 35 dB on night shift; this standard was also violated

Effects of background noise on total noise annoyance

Science.gov (United States)

Willshire, K. F.

1987-01-01

Two experiments were conducted to assess the effects of combined community noise sources on annoyance. The first experiment baseline relationships between annoyance and noise level for three community noise sources (jet aircraft flyovers, traffic and air conditioners) presented individually. Forty eight subjects evaluated the annoyance of each noise source presented at four different noise levels. Results indicated the slope of the linear relationship between annoyance and noise level for the traffic noise was significantly different from that of aircraft and of air conditioner noise, which had equal slopes. The second experiment investigated annoyance response to combined noise sources, with aircraft noise defined as the major noise source and traffic and air conditioner noise as background noise sources. Effects on annoyance of noise level differences between aircraft and background noise for three total noise levels and for both background noise sources were determined. A total of 216 subjects were required to make either total or source specific annoyance judgements, or a combination of the two, for a wide range of combined noise conditions.

Cultural and Demographic Factors Influencing Noise Exposure Estimates from Use of Portable Listening Devices in an Urban Environment

Science.gov (United States)

Fligor, Brian J.; Levey, Sandra; Levey, Tania

2014-01-01

Purpose: This study examined listening levels and duration of portable listening devices (PLDs) used by people with diversity of ethnicity, education, music genre, and PLD manufacturer. The goal was to estimate participants' PLD noise exposure and identify factors influencing user behavior. Method: This study measured listening levels of 160…

Effects of secondary loudspeaker properties on broadband feedforward active duct noise control.

Science.gov (United States)

Chan, Yum-Ji; Huang, Lixi; Lam, James

2013-07-01

Dependence of the performance of feedforward active duct noise control on secondary loudspeaker parameters is investigated. Noise reduction performance can be improved if the force factor of the secondary loudspeaker is higher. For example, broadband noise reduction improvement up to 1.6 dB is predicted by increasing the force factor by 50%. In addition, a secondary loudspeaker with a larger force factor was found to have quicker convergence in the adaptive algorithm in experiment. In simulations, noise reduction is improved in using an adaptive algorithm by using a secondary loudspeaker with a heavier moving mass. It is predicted that an extra broadband noise reduction of more than 7 dB can be gained using an adaptive filter if the force factor, moving mass and coil inductance of a commercially available loudspeaker are doubled. Methods to increase the force factor beyond those of commercially available loudspeakers are proposed.

A Review: Characteristics of Noise Absorption Material

Science.gov (United States)

Amares, S.; Sujatmika, E.; Hong, T. W.; Durairaj, R.; Hamid, H. S. H. B.

2017-10-01

Noise is always treated as a nuisance to human and even noise pollution appears in the environmental causing discomfort. This also concerns the engineering design that tends to cultivate this noise propagation. Solution such as using material to absorb the sound have been widely used. The fundamental of the sound absorbing propagation, sound absorbing characteristics and its factors are minimally debated. Furthermore, the method in order to pertain sound absorbing related to the sound absorption coefficient is also limited, as many studies only contributes in result basis and very little in literature aspect. This paper revolves in providing better insight on the importance of sound absorption and the materials factors in obtaining the sound absorption coefficient.

Maximizing noise energy for noise-masking studies.

Science.gov (United States)

Jules Étienne, Cédric; Arleo, Angelo; Allard, Rémy

2017-08-01

Noise-masking experiments are widely used to investigate visual functions. To be useful, noise generally needs to be strong enough to noticeably impair performance, but under some conditions, noise does not impair performance even when its contrast approaches the maximal displayable limit of 100 %. To extend the usefulness of noise-masking paradigms over a wider range of conditions, the present study developed a noise with great masking strength. There are two typical ways of increasing masking strength without exceeding the limited contrast range: use binary noise instead of Gaussian noise or filter out frequencies that are not relevant to the task (i.e., which can be removed without affecting performance). The present study combined these two approaches to further increase masking strength. We show that binarizing the noise after the filtering process substantially increases the energy at frequencies within the pass-band of the filter given equated total contrast ranges. A validation experiment showed that similar performances were obtained using binarized-filtered noise and filtered noise (given equated noise energy at the frequencies within the pass-band) suggesting that the binarization operation, which substantially reduced the contrast range, had no significant impact on performance. We conclude that binarized-filtered noise (and more generally, truncated-filtered noise) can substantially increase the energy of the noise at frequencies within the pass-band. Thus, given a limited contrast range, binarized-filtered noise can display higher energy levels than Gaussian noise and thereby widen the range of conditions over which noise-masking paradigms can be useful.

Generalised shot noise Cox processes

DEFF Research Database (Denmark)

Møller, Jesper; Torrisi, Giovanni Luca

We introduce a new class of Cox cluster processes called generalised shot-noise processes (GSNCPs), which extends the definition of shot noise Cox processes (SNCPs) in two directions: the point process which drives the shot noise is not necessarily Poisson, and the kernel of the shot noise can...... be random. Thereby a very large class of models for aggregated or clustered point patterns is obtained. Due to the structure of GSNCPs, a number of useful results can be established. We focus first on deriving summary statistics for GSNCPs and next on how to make simulation for GSNCPs. Particularly, results...... for first and second order moment measures, reduced Palm distributions, the -function, simulation with or without edge effects, and conditional simulation of the intensity function driving a GSNCP are given. Our results are exemplified for special important cases of GSNCPs, and we discuss the relation...

A Low Noise Amplifier for Neural Spike Recording Interfaces

Directory of Open Access Journals (Sweden)

Jesus Ruiz-Amaya

2015-09-01

Full Text Available This paper presents a Low Noise Amplifier (LNA for neural spike recording applications. The proposed topology, based on a capacitive feedback network using a two-stage OTA, efficiently solves the triple trade-off between power, area and noise. Additionally, this work introduces a novel transistor-level synthesis methodology for LNAs tailored for the minimization of their noise efficiency factor under area and noise constraints. The proposed LNA has been implemented in a 130 nm CMOS technology and occupies 0.053 mm-sq. Experimental results show that the LNA offers a noise efficiency factor of 2.16 and an input referred noise of 3.8 μVrms for 1.2 V power supply. It provides a gain of 46 dB over a nominal bandwidth of 192 Hz–7.4 kHz and consumes 1.92 μW. The performance of the proposed LNA has been validated through in vivo experiments with animal models.

Active Noise Control for Dishwasher noise

Science.gov (United States)

Lee, Nokhaeng; Park, Youngjin

2016-09-01

The dishwasher is a useful home appliance and continually used for automatically washing dishes. It's commonly placed in the kitchen with built-in style for practicality and better use of space. In this environment, people are easily exposed to dishwasher noise, so it is an important issue for the consumers, especially for the people living in open and narrow space. Recently, the sound power levels of the noise are about 40 - 50 dBA. It could be achieved by removal of noise sources and passive means of insulating acoustical path. For more reduction, such a quiet mode with the lower speed of cycle has been introduced, but this deteriorates the washing capacity. Under this background, we propose active noise control for dishwasher noise. It is observed that the noise is propagating mainly from the lower part of the front side. Control speakers are placed in the part for the collocation. Observation part of estimating sound field distribution and control part of generating the anti-noise are designed for active noise control. Simulation result shows proposed active noise control scheme could have a potential application for dishwasher noise reduction.

Current inversion induced by colored non-Gaussian noise

International Nuclear Information System (INIS)

Bag, Bidhan Chandra; Hu, Chin-Kung

2009-01-01

We study a stochastic process driven by colored non-Gaussian noises. For the flashing ratchet model we find that there is a current inversion in the variation of the current with the half-cycle period which accounts for the potential on–off operation. The current inversion almost disappears if one switches from non-Gaussian (NG) to Gaussian (G) noise. We also find that at low value of the asymmetry parameter of the potential the mobility controlled current is more negative for NG noise as compared to G noise. But at large magnitude of the parameter the diffusion controlled positive current is higher for the former than for the latter. On increasing the noise correlation time (τ), keeping the noise strength fixed, the mean velocity of a particle first increases and then decreases after passing through a maximum if the noise is non-Gaussian. For Gaussian noise, the current monotonically decreases. The current increases with the noise parameter p, 0< p<5/3, which is 1 for Gaussian noise

Reduction of environmental MHz noise for SQUID application

Energy Technology Data Exchange (ETDEWEB)

Araya, T. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: araya@sup.ee.es.osaka-u.ac.jp; Kitamura, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Kamishiro, M. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sakuta, K. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Itozaki, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: itozaki@ee.es.osaka-u.ac.jp

2006-10-01

It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise.

Reduction of environmental MHz noise for SQUID application

International Nuclear Information System (INIS)

Araya, T.; Kitamura, Y.; Kamishiro, M.; Sakuta, K.; Itozaki, H.

2006-01-01

It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise

Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations.

Science.gov (United States)

Fernández-Somoano, Ana; Llop, Sabrina; Aguilera, Inmaculada; Tamayo-Uria, Ibon; Martínez, María Dolores; Foraster, Maria; Ballester, Ferran; Tardón, Adonina

2015-06-18

This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none) to 10 (strong and unbearable); a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606). Significant correlations between NO2 and annoyance from air pollution (0.154) and that from noise (0.181) were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources.

WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Annoyance

Directory of Open Access Journals (Sweden)

Rainer Guski

2017-12-01

Full Text Available Background: This paper describes a systematic review and meta-analyses on effects of environmental noise on annoyance. The noise sources include aircraft, road, and rail transportation noise as well as wind turbines and noise source combinations. Objectives: Update knowledge about effects of environmental noise on people living in the vicinity of noise sources. Methods: Eligible were published studies (2000–2014 providing comparable acoustical and social survey data including exposure-response functions between standard indicators of noise exposure and standard annoyance responses. The systematic literature search in 20 data bases resulted in 62 studies, of which 57 were used for quantitative meta-analyses. By means of questionnaires sent to the study authors, additional study data were obtained. Risk of bias was assessed by means of study characteristics for individual studies and by funnel plots to assess the risk of publication bias. Main Results: Tentative exposure-response relations for percent highly annoyed residents (%HA in relation to noise levels for aircraft, road, rail, wind turbine and noise source combinations are presented as well as meta-analyses of correlations between noise levels and annoyance raw scores, and the OR for increase of %HA with increasing noise levels. Quality of evidence was assessed using the GRADE terminology. The evidence of exposure-response relations between noise levels and %HA is moderate (aircraft and railway or low (road traffic and wind turbines. The evidence of correlations between noise levels and annoyance raw scores is high (aircraft and railway or moderate (road traffic and wind turbines. The evidence of ORs representing the %HA increase by a certain noise level increase is moderate (aircraft noise, moderate/high (road and railway traffic, and low (wind turbines. Strengths and Limitations: The strength of the evidence is seen in the large total sample size encompassing the included studies (e

Preliminary recommendations of the Noise Working Group

International Nuclear Information System (INIS)

Legerton, M.L.

1995-01-01

In 1993 the DTI set up a Working Group largely consisting of independent experts on wind turbine noise. The main objectives of the Working Group were to define a framework which can be used to measure and rate the noise from wind turbines and to provide indicative noise levels thought to offer a reasonable degree of protection to wind farm neighbours and encourage best practice in turbine design and wind farm siting and layout. This paper presents the preliminary recommendations of the Working Group. (Author)

Universal Majorana thermoelectric noise

Science.gov (United States)

Smirnov, Sergey

2018-04-01

Thermoelectric phenomena resulting from an interplay between particle flows induced by electric fields and temperature inhomogeneities are extremely insightful as a tool providing substantial knowledge about the microscopic structure of a given system. By tuning, e.g., parameters of a nanoscopic system coupled via tunneling mechanisms to two contacts, one may achieve various situations where the electric current induced by an external bias voltage competes with the electric current excited by the temperature difference of the two contacts. Even more exciting physics emerges when the system's electronic degrees freedom split to form Majorana fermions which make the thermoelectric dynamics universal. Here, we propose revealing these unique universal signatures of Majorana fermions in strongly nonequilibrium quantum dots via noise of the thermoelectric transport beyond linear response. It is demonstrated that whereas mean thermoelectric quantities are only universal at large-bias voltages, the noise of the electric current excited by an external bias voltage and the temperature difference of the contacts is universal at any bias voltage. We provide truly universal, i.e., independent of the system's parameters, thermoelectric ratios between nonlinear response coefficients of the noise and mean current at large-bias voltages where experiments may easily be performed to uniquely detect these truly universal Majorana thermoelectric signatures.

Noise Analysis of MAIA System and Possible Noise Suppression

Czech Academy of Sciences Publication Activity Database

Švihlík, J.; Fliegel, K.; Koten, Pavel; Vítek, S.; Páta, P.

2011-01-01

Roč. 20, č. 1 (2011), s. 110-117 ISSN 1210-2512. [International Conference on Telecommunications and Signal Processing /33./ - TSP 2010. Baden near Vienna, 17.08.2010-20.08.2010] Institutional research plan: CEZ:AV0Z10030501 Keywords : MAIA * meteor * noise analysis Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.739, year: 2011

Sustainable Innovation - Driving Factors in Large Firms

OpenAIRE

Alderin, Clara; Do, Thao

2016-01-01

During recent years, there has been a growing interest in sustainable innovation both in academia and in practice. Our qualitative, multiple case study examines this emerging field in the context of large firms. By doing so, this thesis contributes to the understanding of the concept as well as the underlying factors driving sustainable innovation. Theory highlighted both external and internal factors in firms’ sustainable innovation engagement. The empirical evidence identifies five key fact...

Assessment of engine noise shielding by the wings of current turbofan aircraft

NARCIS (Netherlands)

Alves Vieira, A.E.; Snellen, M.; Simons, D.G.; Gibbs, B.

2017-01-01

The shielding of engine noise by the aircraft wings and fuselage can lead to a significant reduction on perceived noise on ground. Most research on noise shielding is focused on BlendedWing Body (BWB) configurations because of the large dimension of the fuselage. However, noise shielding is also

Characterization of a subset of large amplitude noise events in VIRGO science run 1 (VSR1)

International Nuclear Information System (INIS)

Del Prete, M

2009-01-01

We report about a characterization study of a subset of large amplitude noise events present in the main data channel of the VIRGO detector. The main motivation of this study is the identification of auxiliary channels which can be used to define veto procedures. We characterized large amplitude events both in the time and in the frequency domain. We found evidence of coincidences among these and disturbances detected by magnetometer's sensors or inside the main power supply. In some cases the disturbances were produced by events in the VIRGO environment such as lightnings, main power supply glitches and airplane traffic. We have found two auxiliary channels that can be used to veto events generated by main power supply glitches or lightnings. A procedure to clean the main channel based on them has been successfully tested. We have also identified two auxiliary channels which are useful for the identification of events generated by airplane traffic. These can be used to implement a vetoing procedure both in the time and in the frequency domain.

Characterization of a subset of large amplitude noise events in VIRGO science run 1 (VSR1)

Energy Technology Data Exchange (ETDEWEB)

Del Prete, M [Universita di Pisa, Lungarno Pacinotti, 43, 56126 Pisa Instituto Nazionale di Fisica Nucleare sez. di Pisa, ED C polo Fibonacci, Via F Buonarroti 2, 56127, Pisa (Italy)

2009-10-21

We report about a characterization study of a subset of large amplitude noise events present in the main data channel of the VIRGO detector. The main motivation of this study is the identification of auxiliary channels which can be used to define veto procedures. We characterized large amplitude events both in the time and in the frequency domain. We found evidence of coincidences among these and disturbances detected by magnetometer's sensors or inside the main power supply. In some cases the disturbances were produced by events in the VIRGO environment such as lightnings, main power supply glitches and airplane traffic. We have found two auxiliary channels that can be used to veto events generated by main power supply glitches or lightnings. A procedure to clean the main channel based on them has been successfully tested. We have also identified two auxiliary channels which are useful for the identification of events generated by airplane traffic. These can be used to implement a vetoing procedure both in the time and in the frequency domain.

Noise analysis of a digital radiography system

International Nuclear Information System (INIS)

Arnold, B.A.; Scheibe, P.O.

1984-01-01

The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter, time jitter, structure noise in the image intensifier, and video recorder electronic noise. A new noise source was identified, which results from the interplay of fixed pattern noise and the lack of image registration. This type of noise may result from image-intensifier structure noise in combination with TV camera time jitter or recorder time jitter. A similar noise source is generated from the interplay of patient absorption inhomogeneities and patient motion or image re-registration. Signal-to-noise ratios were measured for a variety of experimental conditions using subtracted digital images. Image-intensifier structure noise was shown to be a dominant noise source in unsubtracted images at medium to high radiation exposure levels. A total-system signal-to-noise ratio (SNR) of 750:1 was measured for an input exposure of 1 mR/frame at the image intensifier input. The effect of scattered radiation on subtracted image SNR was found to be greater than previously reported. The detail SNR was found to vary approximately as one plus the scatter degradation factor. Quantization error noise with 8-bit image processors (signal-to-noise ratio of 890:1) was shown to be of increased importance after recent improvements in TV cameras. The results of the analysis are useful both in the design of future digital radiography systems and the selection of optimum clinical techniques

Precise Characterization and Multiobjective Optimization of Low Noise Amplifiers

Directory of Open Access Journals (Sweden)

J. Dobes

2015-09-01

Full Text Available Although practically all function blocks of the satellite navigation receivers are realized using the CMOS digital integrated circuits, it is appropriate to create a separate low noise antenna preamplifier based on a low noise pHEMT. Such an RF front end can be strongly optimized to attain a suitable tradeoff between the noise figure and transducer power gain. Further, as all the four principal navigation systems (GPS, GLONASS, Galileo, and COMPASS work in similar frequency bands (roughly from 1.1 to 1.7 GHz, it is reasonable to create the low noise preamplifier for all of them. In the paper, a sophisticated method of the amplifier design is suggested based on multiobjective optimization. A substantial improvement of a standard optimization method is also outlined to satisfy a uniform coverage of Pareto front. Moreover, for enhancing efficiency of many times repeated solutions of large linear systems during the optimization, a new modification of the Markowitz criterion is suggested compatible with fast modes of the LU factorization. Extraordinary attention was also given to the accuracy of modeling. First, an extraction of pHEMT model parameters was performed including its noise part, and several models were compared. The extraction was carried out by an original identification procedure based on a combination of metaheuristic and direct methods. Second, the equations of the passive elements (including transmission lines and T-splitters were carefully defined using frequency dispersion of their parameters as Q, ESR, etc. Third, an optimal selection of the operating point and essential passive elements was performed using the improved optimization method. Finally, the s-parameters and noise figure of the amplifier were measured, and stability and third-order intermodulation products were also checked.

Four-jet impingement: Noise characteristics and simplified acoustic model

International Nuclear Information System (INIS)

Brehm, C.; Housman, J.A.; Kiris, C.C.; Barad, M.F.; Hutcheson, F.V.

2017-01-01

Highlights: • Large eddy simulation of unique four jet impingement configuration. • Characterization of flow features using POD, FFT, and wavelet decomposition. • Noise source identification utilizing causality method. • Development of simplified acoustic model utilizing equivalent source method. • Comparison with experimental data from BENS experiment. - Abstract: The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order weighted essentially non-oscillatory scheme. Although these types of impinging jet configurations have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortical flow structures in the center of the four-jet impingement region. The causality method based on Lighthills acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a simplified acoustic model of the four-jet impingement device by utilizing the equivalent source method. Finally, three linear acoustic four-jet impingement models of the four-jet impingement device are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.

Near-source noise suppression of AMT by compressive sensing and mathematical morphology filtering

Science.gov (United States)

Li, Guang; Xiao, Xiao; Tang, Jing-Tian; Li, Jin; Zhu, Hui-Jie; Zhou, Cong; Yan, Fa-Bao

2017-12-01

In deep mineral exploration, the acquisition of audio magnetotelluric (AMT) data is severely affected by ambient noise near the observation sites; This near-field noise restricts investigation depths. Mathematical morphological filtering (MMF) proved effective in suppressing large-scale strong and variably shaped noise, typically low-frequency noise, but can not deal with pulse noise of AMT data. We combine compressive sensing and MMF. First, we use MMF to suppress the large-scale strong ambient noise; second, we use the improved orthogonal match pursuit (IOMP) algorithm to remove the residual pulse noise. To remove the noise and protect the useful AMT signal, a redundant dictionary that matches with spikes and is insensitive to the useful signal is designed. Synthetic and field data from the Luzong field suggest that the proposed method suppresses the near-source noise and preserves the signal well; thus, better results are obtained that improve the output of either MMF or IOMP.

Multiple target sound quality balance for hybrid electric powertrain noise

Science.gov (United States)

Mosquera-Sánchez, J. A.; Sarrazin, M.; Janssens, K.; de Oliveira, L. P. R.; Desmet, W.

2018-01-01

The integration of the electric motor to the powertrain in hybrid electric vehicles (HEVs) presents acoustic stimuli that elicit new perceptions. The large number of spectral components, as well as the wider bandwidth of this sort of noises, pose new challenges to current noise, vibration and harshness (NVH) approaches. This paper presents a framework for enhancing the sound quality (SQ) of the hybrid electric powertrain noise perceived inside the passenger compartment. Compared with current active sound quality control (ASQC) schemes, where the SQ improvement is just an effect of the control actions, the proposed technique features an optimization stage, which enables the NVH specialist to actively implement the amplitude balance of the tones that better fits into the auditory expectations. Since Loudness, Roughness, Sharpness and Tonality are the most relevant SQ metrics for interior HEV noise, they are used as performance metrics in the concurrent optimization analysis, which, eventually, drives the control design method. Thus, multichannel active sound profiling systems that feature cross-channel compensation schemes are guided by the multi-objective optimization stage, by means of optimal sets of amplitude gain factors that can be implemented at each single sensor location, while minimizing cross-channel effects that can either degrade the original SQ condition, or even hinder the implementation of independent SQ targets. The proposed framework is verified experimentally, with realistic stationary hybrid electric powertrain noise, showing SQ enhancement for multiple locations within a scaled vehicle mock-up. The results show total success rates in excess of 90%, which indicate that the proposed method is promising, not only for the improvement of the SQ of HEV noise, but also for a variety of periodic disturbances with similar features.

Survey on Johnson noise thermometry for temperature instrumentation

International Nuclear Information System (INIS)

Hwang, I. K.; Kim, Y. K.; Kim, J. S.; Moon, B. S.

2002-01-01

Johnson Noise Thermometry is an drift-free temperature measurement method which is able to maintain the best accuracy without calibration for a long period. Resistance Temperature Detectors (RTDs) and Thermocouples used widely in power plants have the drift problem which causes a measurement error. Despite the advantage of Johnson Noise thermometry, it has not been used because it is very sensitive to electromagnetic noise and environment. It also requires more complicated signal processing methods. This paper presents the characteristics of Johnson Noise thermometry and various implementation method proposed over the past decades time period. The key factor in development of a noise thermometer is how to extract the tiny noise signal from the sensor and discriminate out the unnecessary noise interference from the environments. The new digital technology of fast signal processing skill will useful to challenge the existing problems fir commercialization of noise thermometry

Improved CEEMDAN-wavelet transform de-noising method and its application in well logging noise reduction

Science.gov (United States)

Zhang, Jingxia; Guo, Yinghai; Shen, Yulin; Zhao, Difei; Li, Mi

2018-06-01

The use of geophysical logging data to identify lithology is an important groundwork in logging interpretation. Inevitably, noise is mixed in during data collection due to the equipment and other external factors and this will affect the further lithological identification and other logging interpretation. Therefore, to get a more accurate lithological identification it is necessary to adopt de-noising methods. In this study, a new de-noising method, namely improved complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN)-wavelet transform, is proposed, which integrates the superiorities of improved CEEMDAN and wavelet transform. Improved CEEMDAN, an effective self-adaptive multi-scale analysis method, is used to decompose non-stationary signals as the logging data to obtain the intrinsic mode function (IMF) of N different scales and one residual. Moreover, one self-adaptive scale selection method is used to determine the reconstruction scale k. Simultaneously, given the possible frequency aliasing problem between adjacent IMFs, a wavelet transform threshold de-noising method is used to reduce the noise of the (k-1)th IMF. Subsequently, the de-noised logging data are reconstructed by the de-noised (k-1)th IMF and the remaining low-frequency IMFs and the residual. Finally, empirical mode decomposition, improved CEEMDAN, wavelet transform and the proposed method are applied for analysis of the simulation and the actual data. Results show diverse performance of these de-noising methods with regard to accuracy for lithological identification. Compared with the other methods, the proposed method has the best self-adaptability and accuracy in lithological identification.

Road Traffic Noise Pollution Analysis for Cernavoda City

Science.gov (United States)

Manea, L.; Manea, A.; Florea, D.; Tarulescu, S.

2017-10-01

In the present paper was studied the noise pollution in Cernavodă city. The noise measurements were made for nine intersections from different city areas. Noise measurements were taken for three chosen routes with high population density, heavy traffic, commercial and residential buildings. Average, maximum and minimum values were collected and compared with standards. The impact of road traffic noise on the community depends on various factors such as road location and design, land use planning measures, building design, traffic composition, driver behaviour and the relief. In the study area 9 locations are identified to measure noise level. By using sound level meter noise levels are measured at different peak sessions i.e. morning, afternoon and evening. The presented values were collected for evening rush hour.

Development of an advanced noise propagation model for noise optimization in wind farm

DEFF Research Database (Denmark)

Barlas, Emre

2017-01-01

Increasing demand in renewable energy has resulted in large wind energy deployment. Even though wind turbines are among the most environmentally friendly way of generating electricity, the noise emitted by them is one of the main obstacles for further installation. Wind farm developers rely...... wind directions or time of the day). The latter causes turbines to be located at less resourceful sites in advance. Both of these scenarios increase the cost of energy. Hence there is a need for more accurate noise mapping tools. The thesis addresses this issue via development of a new tool based...... field sound pressure levels are addressed both in steady and unsteady manner. Enhanced far fields amplitude modulation is observed and associated with the wake dynamics and the rotating blades. Lastly, the developed tool is used for an onshore wind farm noise prediction taking the terrain and the flow...

Intrinsic and extrinsic factors influencing large African herbivore movements

NARCIS (Netherlands)

Venter, J.A.; Prins, H.H.T.; Mashanova, A.; Boer, de W.F.; Slotow, R.

2015-01-01

Understanding environmental as well as anthropogenic factors that influence large herbivore ecological patterns and processes should underpin their conservation and management. We assessed the influence of intrinsic, extrinsic environmental and extrinsic anthropogenic factors on movement behaviour

Investigation of mode partition noise in Fabry-Perot laser diode

Science.gov (United States)

Guo, Qingyi; Deng, Lanxin; Mu, Jianwei; Li, Xun; Huang, Wei-Ping

2014-09-01

Passive optical network (PON) is considered as the most appealing access network architecture in terms of cost-effectiveness, bandwidth management flexibility, scalability and durability. And to further reduce the cost per subscriber, a Fabry-Perot (FP) laser diode is preferred as the transmitter at the optical network units (ONUs) because of its lower cost compared to distributed feedback (DFB) laser diode. However, the mode partition noise (MPN) associated with the multi-longitudinal-mode FP laser diode becomes the limiting factor in the network. This paper studies the MPN characteristics of the FP laser diode using the time-domain simulation of noise-driven multi-mode laser rate equation. The probability density functions are calculated for each longitudinal mode. The paper focuses on the investigation of the k-factor, which is a simple yet important measure of the noise power, but is usually taken as a fitted or assumed value in the penalty calculations. In this paper, the sources of the k-factor are studied with simulation, including the intrinsic source of the laser Langevin noise, and the extrinsic source of the bit pattern. The photon waveforms are shown under four simulation conditions for regular or random bit pattern, and with or without Langevin noise. The k-factors contributed by those sources are studied with a variety of bias current and modulation current. Simulation results are illustrated in figures, and show that the contribution of Langevin noise to the k-factor is larger than that of the random bit pattern, and is more dominant at lower bias current or higher modulation current.

Survey Situation and Factors Affect on Hearing Protection Large Industry Workers of Hamadan City in 2001-2002

Directory of Open Access Journals (Sweden)

F. Emami

2004-01-01

Full Text Available Noise induced hearing loss in adults is the most cause of sensory neural hearing loss after the presbycusis and industry workers severity affect by degenerative results of that. Three large works of Hamadan city which had more than 200 Workers were selected in this demonstrative quest . The mean of sound pressure level evaluated with sound level meter which amount to 82-95 dB. Total exposed workers with higher noise than 85 dB evaluated by pure tone audiometery and otoscopic evaluation and the means of hearing thresholds in four frequency :0.5,1,2,4 kHz balanced with previously . Method of concentration data was direct observation and questionnaire . 809 workers in local works exposed to invasive noise . 20.02% of them hadn’t any hearing protector and 79.98% had , which combinated of wax or dry cotton and fiber glass (76.20%, earplug (7.42%and earmuff(16.38%. The means of hearing thresholds workers with protector equal to 43.36 dB and without that was equal to 44.03 dB (t=0.29, Pv<0.05. Highest percentage quantity in two groups related to age –bracket 40-49 years old. Women with protection(9.43%were more than without protector(3.7% while the most percentage related to men without protector (96.3% in contrast to 90.57%.In totally highest percentage quantity of NIHL was in workers with past-working more than 15 years (67.54% with protector , 67.28%without protector. For awareness of degenerative results the noise in hearing large industry workers of Hamadan city 75% insignificant and 25% had efficient awareness . Not using of protectors by 20.2% of worker showing light awareness to degenerative results of noise on hearing system and poor educational healthing and noting difference in means of hearing loss at protected group on basis duration of using that, strikes the process of hearing conservation program is superficial.

Identification of Macroeconomic Factors in Large Panels

DEFF Research Database (Denmark)

Bork, Lasse; Dewachter, Hans; Houssa, Romain

standard practices in the SVAR literature. Estimators based on the EM algorithm are developped. We apply this framework to a large panel of US monthly macroeconomic series. In particular, we identify nine macroeconomic factors and discuss the economic impact of monetary policy stocks. The results...

Noise annoyance from wind turbines a review

International Nuclear Information System (INIS)

Pedersen, Eja

2003-08-01

This study summarises present knowledge on noise perception and annoyances from wind turbines in areas were people live or spend recreation time. There are two main types of noise from a wind turbine: mechanical noise and aerodynamic noise. The aerodynamic noise emits from the rotor blades passing the air. It has a swishing character with a modulation that makes it noticeable from the background noise. This part of the wind turbine noise was found to be the most annoying. Field studies performed among people living in the vicinity of wind turbines showed that there was a correlation between sound pressure level and noise annoyance, but annoyance was also influenced by visual factors such as the attitude to wind turbines' impact on the landscape. Noise annoyance was found at lower sound pressure levels than in studies of annoyance from traffic noise. There is no scientific evidence that noise at levels created by wind turbines could cause health problems other than annoyance. No studies on noise from wind turbines in wilderness areas have been found, but the reaction to other noise sources such as aircraft have been studied. In recreational areas, the expectation of quietness is high among visitors, but wind turbines are, in contrary to aircraft, stationary and could be avoided by recreationists. The visual impact of wind turbines might though be the dominant source of annoyance. Regulations on noise from wind turbines are based on different principles. Some states, e.g. Denmark, have a special legislation concerning wind turbines, while others, like Sweden, have used recommendations originally developed for a different noise source. The noise level could either be absolute, as in Germany, or related to the background noise level as in France. This background noise level could be standardised, measured or related to wind speed

Relationship between noise and job stress at a private thread spinning company

Directory of Open Access Journals (Sweden)

Andi Mursali

2009-04-01

Full Text Available Noise exposure is one of the major occupational hazards in many places, and has several health effects, including hearing loss and psychological effects such as sleep disturbances and mental stress. The objective of this research was to determine the relationship between noise and stress and other risk factors that affect job stress. A cross-sectional comparative design involved a total of 326 workers consisting of 220 workers in high noise conditions and 106 workers in low noise conditions. The data were collected directly from the respondents by filling out the questionnaire on worker characteristics, the stress diagnostic questionnaire, and the symptom checklist 90, through discussions with company management, and by measurement of noise levels. The job stress prevalence in workers in high noise conditions was 55% and in those in low noise conditions 24.5%. The results showed that risk factors such as gender of workers, noise conditions, habitual use of ear plugs, shift work, and work stressors had a significant relationship with job stress. Multivariate analysis indicated that the habit of using earplugs was a dominant risk factor causing job stress. The prevalence of job stress in high noise conditions was higher than that in workers in low noise conditions. Noise conditions have a significant relationship with job stress (OR=2.46; 95% CI 1.33 - 4.55. Workers in high noise conditions who did not always use or never had used ear plugs had a higher chance of experiencing stress than those in low noise conditions who did not need ear plugs (OR=21.76; 95% CI 8.09 - 58.52. This study supported that noise exerts its health effect via stress, since noise often raise stress in various ways.

Phase noise and frequency stability in oscillators

CERN Document Server

Rubiola, Enrico

2009-01-01

Presenting a comprehensive account of oscillator phase noise and frequency stability, this practical text is both mathematically rigorous and accessible. An in-depth treatment of the noise mechanism is given, describing the oscillator as a physical system, and showing that simple general laws govern the stability of a large variety of oscillators differing in technology and frequency range. Inevitably, special attention is given to amplifiers, resonators, delay lines, feedback, and flicker (1/f) noise. The reverse engineering of oscillators based on phase-noise spectra is also covered, and end-of-chapter exercises are given. Uniquely, numerous practical examples are presented, including case studies taken from laboratory prototypes and commercial oscillators, which allow the oscillator internal design to be understood by analyzing its phase-noise spectrum. Based on tutorials given by the author at the Jet Propulsion Laboratory, international IEEE meetings, and in industry, this is a useful reference for acade...

Shinkansen noise: Research and achievements in countermeasures for Shinkansen noise

Science.gov (United States)

Kikuchi, I.

1988-01-01

In 1982, the Tohoku and Joetsu Shinkansen lines were opened. The result is the present Shinkansen network that runs through Japan from north to south, leading to a remarkable improvement in railway services, together with the provision of new, efficient connections with conventional lines. Since the opening of the Tokaido Shinkansen, the high utility of the Shinkansen as a high speed, large volume, and safe mode of transport has been gaining a high reputation. On the other hand, social demands for environmental preservation increased in strength with the advent of the period of Japan's high economic growth. Such demands were posed in the form of complaints about air and water pollution and noise from transportation. The problems of noise and vibration from Shinkansen train operation were posed mainly in relation to railway viaducts in urban areas. The Japanese National Railways (JNR) has made all-out efforts in technical development for noise reduction, obtained many achievements, and put them into practical use one by one on the Shinkansen lines. In the early stage of studies, there were many virgin areas for JNR staff, such as measurement technology, estimation methods, and noise alleviation technology. With the start of full-scale testing at a general test center in 1975, various studies and the development of effective measures made a great step forward. In March 1985, the maximum speed on the Tohoku Shinkansen was increased to 240 km/h, enhancing the Shinkansen reputation and resulting in a considerable growth of traffic. As a matter of course, new measures for noise reduction were taken for this line. In view of the history and results of voluminous studies over many years on the Shinkansen noise problem, and also of the roles and surrounding conditions of the Shinkansen as a mode of transport, however, new tasks are being posed concerning such aspects as how to accomplish environmental preservation in the future.

Noise annoyance through railway traffic - a case study.

Science.gov (United States)

Trombetta Zannin, Paulo Henrique; Bunn, Fernando

2014-01-08

This paper describes an assessment of noise caused by railway traffic in a large Latin American city. Measurements were taken of noise levels generated by trains passing through residential neighborhoods with and without blowing their horns. Noise maps were also calculated showing noise pollution generated by the train traffic. In addition - annoyance of the residents - affected by railway noise, was evaluated based on interviews. The measurements indicated that the noise levels generated by the passage of the train with its horn blowing are extremely high, clearly exceeding the daytime limits of equivalent sound pressure level - Leq = 55 dB(A) - established by the municipal laws No 10.625 of the city of Curitiba. The Leq = 45 dB (A) which is the limit for the night period also are exceeded during the passage of trains. The residents reported feeling affected by the noise generated by passing trains, which causes irritability, headaches, poor concentration and insomnia, and 88% of them claimed that nocturnal noise pollution is the most distressing. This study showed that the vast majority of residents surveyed, (69%) believe that the noise of the train can devalue their property.

Effect of external noise on the current response in superlattices

International Nuclear Information System (INIS)

Suqing Duan; Wu Binyi; Wang Zhigang; Zhao Xiangeng

2004-01-01

Within the single-band model and the nearest-neighbor approximation we investigate the effect of external noise on the current response driven by dc-ac field which has a fluctuating component. We find the external noise can destroy the current resonant peaks. When the strength of the external noise becomes enough large, all the current resonant peaks will completely disappear

Proceedings of the Jet Noise Workshop

Science.gov (United States)

Huff, Dennis (Compiler)

2001-01-01

Jet noise has been a major problem for aircraft for nearly 50 years. There has been considerable research performed around the world aimed at identifying ways to reduce jet noise. This work was first intended for turbojet aircraft and later extended to low bypass ratio turbofans. Many of the people who performed this pioneering research have retired or are no longer active in aeroacoustics. After so many years of work in jet noise, it is a challenge to piece together the history of its development through existing publications due to the large volume of documents. It is possible to forget important developments from the past as new researchers tackle similar problems. Therefore, a jet noise workshop was organized by the AeroAcoustics Research Consortium (AARC) with the intent of reviewing research that has been done by experts throughout the world. The forum provided a unique opportunity for current researchers to hear the diverse views from world experts on issues related to jet noise modeling and interpretation of experimental data.

Noise in a-Si:H p-i-n detector diodes

International Nuclear Information System (INIS)

Cho, G.; Qureshi, S.; Drewery, J.S.; Jing, T.; Kaplan, S.N.; Lee, H.; Mireshghi, A.; Perez-Mendez, V.; Wildermuth, D.

1991-10-01

Noise of a-Si:H p-i-n diodes (5 ∼ 50 μm thick) under reverse bias was investigated. The current dependent 1/f type noise was found to be the main noise component at high bias. At low bias the thermal noise from a series resistance of the p-layer and of the metallic contacts is the dominant noise source which is unrelated to the reverse current through the diode. The noise associated with the p-layer resistance decreased significantly on annealing under reverse bias, reducing the total zero bias noise by a factor 2 approximately. The noise recovered to the original value on subsequent annealing without bias. In addition to the resistive noise there seems to be a shaping time independent noise component at zero biased diodes

Judgments of aircraft noise in a traffic noise background

Science.gov (United States)

Powell, C. A.; Rice, C. G.

1975-01-01

An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.

Simulation of cross-talk noise of high energy X-ray detectors

International Nuclear Information System (INIS)

Zhou Rifeng; Zhang Ping; Zhang Zehong

2005-01-01

The signal-noise ratio of detectors and the image quality will be affected by the detector cross-talk noise. The authors use EGSnrc to research the cross-talk noise in the CdWO 4 detector module, and analyze various factors which can bring about the cross-talk noise. The work will facilitate the selection of detector module and offer some parameters for the correction of cross-talk noise with software. (authors)

Characteristic of Noise-induced Hearing Loss among Workers in Construction Industries

Science.gov (United States)

Naadia Mazlan, Ain; Yahya, Khairulzan; Haron, Zaiton; Amsharija Mohamed, Nik; Rasib, Edrin Nazri Abdul; Jamaludin, Nizam; Darus, Nadirah

2018-03-01

Noise-induced hearing loss (NIHL) is among the most common occupational disease in industries. This paper investigates NIHL in construction related industries in Malaysia with particular emphasis on its relation with risk factors. The objectives of this research were to (1) quantify the prevalence of NIHL in construction related industries, and (2) assess the relationship between hearing loss and risk factors and it's characteristic. The study was conducted using 110 NIHL compensation record collected from Social Security Organisation (SOCSO), Malaysia. Risk factors namely area noise, age, temperature, smoking habit, hobby, diabetic and cardiovascular disease were identified and analysed. Results showed that there was no direct relationship between area noise with hearing impairment while there was only low relationship between age and hearing impairment. The range for area noise and age were between 70 to 140 dB(A) and 20 to 70 years, respectively. The other risk factors classified as categorical data and analysed using frequency method. Grade of impairment does not depend solely on area noise but also in combination with age and other risk factors. Characteristic of NIHL prevailed in construction related industries were presented using scatterplots and can serve as a references for future hazard control on site.

Noise-induced polarization switching in complex networks

Science.gov (United States)

Haerter, Jan O.; Díaz-Guilera, Albert; Serrano, M. Ángeles

2017-04-01

The combination of bistability and noise is ubiquitous in complex systems, from biology to social interactions, and has important implications for their functioning and resilience. Here we use a simple three-state dynamical process, in which nodes go from one pole to another through an intermediate state, to show that noise can induce polarization switching in bistable systems if dynamical correlations are significant. In large, fully connected networks, where dynamical correlations can be neglected, increasing noise yields a collapse of bistability to an unpolarized configuration where the three possible states of the nodes are equally likely. In contrast, increased noise induces abrupt and irreversible polarization switching in sparsely connected networks. In multiplexes, where each layer can have a different polarization tendency, one layer is dominant and progressively imposes its polarization state on the other, offsetting or promoting the ability of noise to switch its polarization. Overall, we show that the interplay of noise and dynamical correlations can yield discontinuous transitions between extremes, which cannot be explained by a simple mean-field description.

The need to revitalize our national noise policy

Science.gov (United States)

Lang, William W.; Beranek, Leo L.

2002-05-01

At the present time, our Nation does not have a national noise policy. The Congress attempted to define one with the passage of the Noise Control Act of 1972 as follows: The Congress declares that it is the policy of the United States to promote an environment for all Americans free from noise that jeopardizes their health and welfare. The Act assigned to the Environmental Protection Agency (EPA) the role of leading Federal agency with the task of coordinating the programs of all Federal agencies relating to noise research and noise control. Ten years later (1982), all funds for noise control were withdrawn from the EPA, and today the Nation is without an effective, overall noise policy. Residual responsibility for the control of environmental and occupational noise currently rests with a dozen agencies of the Federal government, as well as State, municipal, and local authorities. But the activities of these organizations are largely uncoordinated, and the enforcement of existing noise control regulations is at best sporadic, and in some cases nonexistent. To assure our quality of life and to minimize the economic impact of potential trade barriers, a study team is recommending that a national noise policy be developed and then implemented in the immediate future.

Noise-Induced Sleep Disturbance in Residences Near Two Civil Airports

Science.gov (United States)

Fidell, Sanford; Howe, Richard R.; Tabachnick, Barbara G.; Pearsons, Karl S.; Sneddon, Matthew D.

1995-01-01

A large-scale field study of noise-induced sleep disturbance was conducted in the vicinities of Stapleton International Airport (DEN) and Denver International Airport (DIA) in anticipation of the closure of the former and opening of the latter. Both indoor and outdoor measurements of aircraft and other nighttime noises were made during four time periods. Measurements were made in 57 homes located as close as feasible to the runway ends of the two airports. Sleep disturbance was measured by several indices of behaviorally confirmed awakening (button pushes upon awakening) and body movement (as measured with wrist-worn actimeters). A total of 2717 subject-nights of observations were made over the course of the study. Although average noise event levels measured outdoors decreased markedly at DEN after closure of the airport and increased slightly at DIA after its opening, indoor noise event levels varied much less in homes near both airports. No large differences were observed in noise-induced sleep disturbance at either airport. Indoor sound exposure levels of noise events were, however, closely related to and good predictors of actimetrically defined motility and arousal.

Anechoic wind tunnel tests on high-speed train bogie aerodynamic noise

OpenAIRE

Latorre Iglesias, E.; Thompson, D.; Smith, M.; Kitagawa, T.; Yamazaki, N.

2016-01-01

Aerodynamic noise becomes a significant noise source at speeds normally reached by high-speed trains. The train bogies are identified as important sources of aerodynamic noise. Due to the difficulty to assess this noise source carrying out field tests, wind tunnel tests offer many advantages. Tests were performed in the large-scale low-noise anechoic wind tunnel at Maibara, Japan, using a 1/7 scale train car and bogie model for a range of flow speeds between 50, 76, 89 and 100 m/s. The depend...

Noise-gating to Clean Astrophysical Image Data

International Nuclear Information System (INIS)

DeForest, C. E.

2017-01-01

I present a family of algorithms to reduce noise in astrophysical images and image sequences, preserving more information from the original data than is retained by conventional techniques. The family uses locally adaptive filters (“noise gates”) in the Fourier domain to separate coherent image structure from background noise based on the statistics of local neighborhoods in the image. Processing of solar data limited by simple shot noise or by additive noise reveals image structure not easily visible in the originals, preserves photometry of observable features, and reduces shot noise by a factor of 10 or more with little to no apparent loss of resolution. This reveals faint features that were either not directly discernible or not sufficiently strongly detected for quantitative analysis. The method works best on image sequences containing related subjects, for example movies of solar evolution, but is also applicable to single images provided that there are enough pixels. The adaptive filter uses the statistical properties of noise and of local neighborhoods in the data to discriminate between coherent features and incoherent noise without reference to the specific shape or evolution of those features. The technique can potentially be modified in a straightforward way to exploit additional a priori knowledge about the functional form of the noise.

Noise-gating to Clean Astrophysical Image Data

Energy Technology Data Exchange (ETDEWEB)

DeForest, C. E. [Southwest Research Institute, 1050 Walnut Street, Boulder, CO (United States)

2017-04-01

I present a family of algorithms to reduce noise in astrophysical images and image sequences, preserving more information from the original data than is retained by conventional techniques. The family uses locally adaptive filters (“noise gates”) in the Fourier domain to separate coherent image structure from background noise based on the statistics of local neighborhoods in the image. Processing of solar data limited by simple shot noise or by additive noise reveals image structure not easily visible in the originals, preserves photometry of observable features, and reduces shot noise by a factor of 10 or more with little to no apparent loss of resolution. This reveals faint features that were either not directly discernible or not sufficiently strongly detected for quantitative analysis. The method works best on image sequences containing related subjects, for example movies of solar evolution, but is also applicable to single images provided that there are enough pixels. The adaptive filter uses the statistical properties of noise and of local neighborhoods in the data to discriminate between coherent features and incoherent noise without reference to the specific shape or evolution of those features. The technique can potentially be modified in a straightforward way to exploit additional a priori knowledge about the functional form of the noise.

Noise characteristics of neutron images obtained by cooled CCD device

International Nuclear Information System (INIS)

Taniguchi, Ryoichi; Sasaki, Ryoya; Okuda, Shuichi; Okamoto, Ken-Ichi; Ogawa, Yoshihiro; Tsujimoto, Tadashi

2009-01-01

The noise characteristics of a cooled CCD device induced by neutron and gamma ray irradiation have been investigated. In the cooled CCD images, characteristic white spot noises (CCD noise) frequently appeared, which have a shape like a pixel in most cases and their brightness is extremely high compared with that of the image pattern. They could be divided into the two groups, fixed pattern noise (FPN) and random noise. The former always appeared in the same position in the image and the latter appeared at any position. In the background image, nearly all of the CCD noises were found to be the FPN, while many of them were the random noise during the irradiation. The random CCD noises increased with irradiation and decreased soon after the irradiation. In the case of large irradiation, a part of the CCD noise remained as the FPN. These facts suggest that the CCD noise is a phenomenon strongly relating to radiation damage of the CCD device.

Noise in attractor networks in the brain produced by graded firing rate representations.

Directory of Open Access Journals (Sweden)

Tristan J Webb

Full Text Available Representations in the cortex are often distributed with graded firing rates in the neuronal populations. The firing rate probability distribution of each neuron to a set of stimuli is often exponential or gamma. In processes in the brain, such as decision-making, that are influenced by the noise produced by the close to random spike timings of each neuron for a given mean rate, the noise with this graded type of representation may be larger than with the binary firing rate distribution that is usually investigated. In integrate-and-fire simulations of an attractor decision-making network, we show that the noise is indeed greater for a given sparseness of the representation for graded, exponential, than for binary firing rate distributions. The greater noise was measured by faster escaping times from the spontaneous firing rate state when the decision cues are applied, and this corresponds to faster decision or reaction times. The greater noise was also evident as less stability of the spontaneous firing state before the decision cues are applied. The implication is that spiking-related noise will continue to be a factor that influences processes such as decision-making, signal detection, short-term memory, and memory recall even with the quite large networks found in the cerebral cortex. In these networks there are several thousand recurrent collateral synapses onto each neuron. The greater noise with graded firing rate distributions has the advantage that it can increase the speed of operation of cortical circuitry.

Unscented Kalman filtering in the additive noise case

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

The unscented Kalman filter(UKF) has four implementations in the additive noise case,according to whether the state is augmented with noise vectors and whether a new set of sigma points is redrawn from the predicted state(which is so-called resampling) for the observation prediction.This paper concerns the differences of performances for those implementations,such as accuracy,adaptability,computational complexity,etc.The conditionally equivalent relationships between the augmented and non-augmented unscented transforms(UTs) are proved for several sampling strategies that are commonly used.Then,we find that the augmented and non-augmented UKFs have the same filter results with the additive measurement noise,but only have the same state predictions with the additive process noise.Resampling is not believed to be necessary in some researches.However,we find out that resampling can be helpful for an adaptive Kalman gain.This will improve the convergence and accuracy of the filter when the large scale state modeling bias or unknown maneuvers occur.Finally,some universal designing principles for a practical UKF are given as follows:1) for the additive observation noise case,it’s better to use the non-augmented UKF;2) for the additive process noise case,when the small state modeling bias or maneuvers are involved,the non-resampling algorithms with state whether augmented or not are candidates for filters;3) the resampling and non-augmented algorithm is the only choice while the large state modeling bias or maneuvers are latent.

Study of the road traffic noise in Erzurum-Turkey

Directory of Open Access Journals (Sweden)

Mahir Gökdag

2012-12-01

Full Text Available Road traffic noise affects a large number of people, especially in urban areas and is generally a major source of complaints. This paper refers to a study of the problem of traffic noise on roads which have been transformed into streets in the city of Erzurum. Noise levels are measured and the impacts suffered by the community are documented. Manual noise measurements were made along 12 streets exploring sources of maximum noise levels. Noise from different types of vehicles driven in a realistic way in inner city traffic was measured. The results from the measurements showed that, of 750 measured events, approximately 5% of the vehicles exceeded 70 dB(A and less than 2% exceeded 80 dB(A maximum noise level. In summary, the result showed that the most important vehicle component as regards the maximum noise level in inner city traffic was a medium-weight vehicle. Among the higher noise levels measured (>80 dB(A this type of vehicle was dominant.

Determination of aircraft noise variability using an acoustic camera

NARCIS (Netherlands)

Merino Martinez, R.; Snellen, M.; Simons, D.G.

2016-01-01

Nowadays, aircraft noise is one of the major problems to be dealt with by the aerospace industry and especially suffered by the residents living in the vicinities of airports. The enforcement of noise control environmental laws around airports is hindered due to the large variability observed in the

Ultrahigh Error Threshold for Surface Codes with Biased Noise

Science.gov (United States)

Tuckett, David K.; Bartlett, Stephen D.; Flammia, Steven T.

2018-02-01

We show that a simple modification of the surface code can exhibit an enormous gain in the error correction threshold for a noise model in which Pauli Z errors occur more frequently than X or Y errors. Such biased noise, where dephasing dominates, is ubiquitous in many quantum architectures. In the limit of pure dephasing noise we find a threshold of 43.7(1)% using a tensor network decoder proposed by Bravyi, Suchara, and Vargo. The threshold remains surprisingly large in the regime of realistic noise bias ratios, for example 28.2(2)% at a bias of 10. The performance is, in fact, at or near the hashing bound for all values of the bias. The modified surface code still uses only weight-4 stabilizers on a square lattice, but merely requires measuring products of Y instead of Z around the faces, as this doubles the number of useful syndrome bits associated with the dominant Z errors. Our results demonstrate that large efficiency gains can be found by appropriately tailoring codes and decoders to realistic noise models, even under the locality constraints of topological codes.

The Effect of Noise on Human Performance: A Clinical Trial

Directory of Open Access Journals (Sweden)

P Nassiri

2013-04-01

Full Text Available Background: Noise is defined as unwanted or meaningless sound that apart from auditory adverse health effects may distract attention from cues that are important for task performance. Human performance is influenced by many job-related factors and workplace conditions including noise level. Objective: To study the effect of noise on human performance. Methods: The participants included 40 healthy male university students. The experimental design consisted of 3 (sound pressure level x 3 (noise schedule x 2 (noise type factors. To investigate occupational skill performance, some specific test batteries were used: 1 steadiness test, 2 Minnesota manual dexterity test, 3 hand tool dexterity test, and 4 two-arm coordination test. Time duration of test completion was measured as speed response; to determine error response, the time taken during committing an error by participants while performing a task was measured. Results: Speed response obtained from the 4 tests in combined conditions of noise schedule, harmonic index, and sound pressure level was highest for (intermittent, treble, 95 dB, (continuous, treble, 95 dB, (continuous, treble, 85 dB and (intermittent, treble, 95 dB, respectively. Conclusion: Treble noise was found significant in reducing human performance; also, intermittent noise, especially at high pressure levels, was responsible for worsening environmental conditions during performing a task.

Noise emissions of cooling towers; Geraeuschemissionen von Kuehltuermen

Energy Technology Data Exchange (ETDEWEB)

Hinkelmann, Dirk [Mueller-BBM GmbH, Gelsenkirchen (Germany)

2013-09-01

Cooling towers are often large structures with high sound emission. The impact of water drops on the water surface in the collecting basin leads to the generation of middle- and high-frequency noise that is emitted via the air intake opening and the outlet. In forced-draft cooling towers, additional noise is generated by drives and fans. The sound emissions can be predicted by means of empirical calculation models. In this way, noise control measures can be taken into account already at an early phase of planning. Different, proven measures for reduction of sound emissions are taken depending on cooling tower design. Regulations on noise acceptance testing for cooling towers are given in various standards. (orig.)

Confusion noise from LISA capture sources

International Nuclear Information System (INIS)

Barack, Leor; Cutler, Curt

2004-01-01

Captures of compact objects (COs) by massive black holes (MBHs) in galactic nuclei will be an important source for LISA, the proposed space-based gravitational wave (GW) detector. However, a large fraction of captures will not be individually resolvable - either because they are too distant, have unfavorable orientation, or have too many years to go before final plunge - and so will constitute a source of 'confusion noise', obscuring other types of sources. In this paper we estimate the shape and overall magnitude of the GW background energy spectrum generated by CO captures. This energy spectrum immediately translates to a spectral density S h capt (f) for the amplitude of capture-generated GWs registered by LISA. The overall magnitude of S h capt (f) is linear in the CO capture rates, which are rather uncertain; therefore we present results for a plausible range of rates. S h capt (f) includes the contributions from both resolvable and unresolvable captures, and thus represents an upper limit on the confusion noise level. We then estimate what fraction of S h capt (f) is due to unresolvable sources and hence constitutes confusion noise. We find that almost all of the contribution to S h capt (f) coming from white dwarf and neutron star captures, and at least ∼30% of the contribution from black hole captures, is from sources that cannot be individually resolved. Nevertheless, we show that the impact of capture confusion noise on the total LISA noise curve ranges from insignificant to modest, depending on the rates. Capture rates at the high end of estimated ranges would raise LISA's overall (effective) noise level [fS h eff (f)] 1/2 by at most a factor ∼2 in the frequency range 1-10 mHz, where LISA is most sensitive. While this slightly elevated noise level would somewhat decrease LISA's sensitivity to other classes of sources, we argue that, overall, this would be a pleasant problem for LISA to have: It would also imply that detection rates for CO captures

Long-term exposure to road traffic noise, ambient air pollution, and cardiovascular risk factors in the HUNT and lifelines cohorts.

Science.gov (United States)

Cai, Yutong; Hansell, Anna L; Blangiardo, Marta; Burton, Paul R; de Hoogh, Kees; Doiron, Dany; Fortier, Isabel; Gulliver, John; Hveem, Kristian; Mbatchou, Stéphane; Morley, David W; Stolk, Ronald P; Zijlema, Wilma L; Elliott, Paul; Hodgson, Susan

2017-08-01

Blood biochemistry may provide information on associations between road traffic noise, air pollution, and cardiovascular disease risk. We evaluated this in two large European cohorts (HUNT3, Lifelines). Road traffic noise exposure was modelled for 2009 using a simplified version of the Common Noise Assessment Methods in Europe (CNOSSOS-EU). Annual ambient air pollution (PM10, NO2) at residence was estimated for 2007 using a Land Use Regression model. The statistical platform DataSHIELD was used to pool data from 144 082 participants aged ≥20 years to enable individual-level analysis. Generalized linear models were fitted to assess cross-sectional associations between pollutants and high-sensitivity C-reactive protein (hsCRP), blood lipids and for (Lifelines only) fasting blood glucose, for samples taken during recruitment in 2006-2013. Pooling both cohorts, an inter-quartile range (IQR) higher day-time noise (5.1 dB(A)) was associated with 1.1% [95% confidence interval (95% CI: 0.02-2.2%)] higher hsCRP, 0.7% (95% CI: 0.3-1.1%) higher triglycerides, and 0.5% (95% CI: 0.3-0.7%) higher high-density lipoprotein (HDL); only the association with HDL was robust to adjustment for air pollution. An IQR higher PM10 (2.0 µg/m3) or NO2 (7.4 µg/m3) was associated with higher triglycerides (1.9%, 95% CI: 1.5-2.4% and 2.2%, 95% CI: 1.6-2.7%), independent of adjustment for noise. Additionally for NO2, a significant association with hsCRP (1.9%, 95% CI: 0.5-3.3%) was seen. In Lifelines, an IQR higher noise (4.2 dB(A)) and PM10 (2.4 µg/m3) was associated with 0.2% (95% CI: 0.1-0.3%) and 0.6% (95% CI: 0.4-0.7%) higher fasting glucose respectively, with both remaining robust to adjustment for air/noise pollution. Long-term exposures to road traffic noise and ambient air pollution were associated with blood biochemistry, providing a possible link between road traffic noise/air pollution and cardio-metabolic disease risk. Published on behalf of the European Society of

Simulation-Based Prediction of Equivalent Continuous Noises during Construction Processes.

Science.gov (United States)

Zhang, Hong; Pei, Yun

2016-08-12

Quantitative prediction of construction noise is crucial to evaluate construction plans to help make decisions to address noise levels. Considering limitations of existing methods for measuring or predicting the construction noise and particularly the equivalent continuous noise level over a period of time, this paper presents a discrete-event simulation method for predicting the construction noise in terms of equivalent continuous level. The noise-calculating models regarding synchronization, propagation and equivalent continuous level are presented. The simulation framework for modeling the noise-affected factors and calculating the equivalent continuous noise by incorporating the noise-calculating models into simulation strategy is proposed. An application study is presented to demonstrate and justify the proposed simulation method in predicting the equivalent continuous noise during construction. The study contributes to provision of a simulation methodology to quantitatively predict the equivalent continuous noise of construction by considering the relevant uncertainties, dynamics and interactions.

A variational Bayesian method to inverse problems with impulsive noise

KAUST Repository

Jin, Bangti

2012-01-01

We propose a novel numerical method for solving inverse problems subject to impulsive noises which possibly contain a large number of outliers. The approach is of Bayesian type, and it exploits a heavy-tailed t distribution for data noise to achieve

Quantum noise in a terahertz hot electron bolometer mixer

OpenAIRE

Zhang, W.; Khosropanah, P.; Gao, J. R.; Kollberg, E. L.; Yngvesson, K. S.; Bansal, T.; Barends, R.; Klapwijk, T. M.

2010-01-01

We have measured the noise temperature of a single, sensitive superconducting NbN hot electron bolometer (HEB) mixer in a frequency range from 1.6 to 5.3 THz, using a setup with all the key components in vacuum. By analyzing the measured receiver noise temperature using a quantum noise (QN) model for HEB mixers, we confirm the effect of QN. The QN is found to be responsible for about half of the receiver noise at the highest frequency in our measurements. The ?-factor (the quantum efficiency ...

Design of low noise class D amplifiers using an integrated filter

International Nuclear Information System (INIS)

Wang Haishi; Zhang Bo

2012-01-01

This paper investigates the noise sources in a single-ended class D amplifier (SECDA) and suggests corresponding ways to lower the noise. The total output noise could be expressed as a function of the gain and noises from different sources. According to the function, the bias voltage (V B ) is a primary noise source, especially for a SECDA with a large gain. A low noise SECDA is obtained by integrating a filter into the SECDA to lower the noise of the V B . The filter utilizes an active resister and an 80 pF capacitance to get a 3 Hz pole. A noise test and fast Fourier transform analysis show that the noise performance of this SECDA is the same as that of a SECDA with an external filter. (semiconductor integrated circuits)

Quantum noise and superluminal propagation

International Nuclear Information System (INIS)

Segev, Bilha; Milonni, Peter W.; Babb, James F.; Chiao, Raymond Y.

2000-01-01

Causal ''superluminal'' effects have recently been observed and discussed in various contexts. The question arises whether such effects could be observed with extremely weak pulses, and what would prevent the observation of an ''optical tachyon.'' Aharonov, Reznik, and Stern (ARS) [Phys. Rev. Lett. 81, 2190 (1998)] have argued that quantum noise will preclude the observation of a superluminal group velocity when the pulse consists of one or a few photons. In this paper we reconsider this question both in a general framework and in the specific example, suggested by Chiao, Kozhekin, and Kurizki (CKK) [Phys. Rev. 77, 1254 (1996)], of off-resonant, short-pulse propagation in an optical amplifier. We derive in the case of the amplifier a signal-to-noise ratio that is consistent with the general ARS conclusions when we impose their criteria for distinguishing between superluminal propagation and propagation at the speed c. However, results consistent with the semiclassical arguments of CKK are obtained if weaker criteria are imposed, in which case the signal can exceed the noise without being ''exponentially large.'' We show that the quantum fluctuations of the field considered by ARS are closely related to superfluorescence noise. More generally, we consider the implications of unitarity for superluminal propagation and quantum noise and study, in addition to the complete and truncated wave packets considered by ARS, the residual wave packet formed by their difference. This leads to the conclusion that the noise is mostly luminal and delayed with respect to the superluminal signal. In the limit of a very weak incident signal pulse, the superluminal signal will be dominated by the noise part, and the signal-to-noise ratio will therefore be very small. (c) 2000 The American Physical Society

Temperature dependence of shot noise in double barrier magnetic tunnel junctions

Science.gov (United States)

Niu, Jiasen; Liu, Liang; Feng, J. F.; Han, X. F.; Coey, J. M. D.; Zhang, X.-G.; Wei, Jian

2018-03-01

Shot noise reveals spin dependent transport properties in a magnetic tunnel junction. We report measurement of shot noise in CoFeB/MgO/CoFeB/MgO/CoFeB double barrier magnetic tunnel junctions, which shows a strong temperature dependence. The Fano factor used to characterize shot noise increases with decreasing temperature. A sequential tunneling model can be used to account for these results, in which a larger Fano factor results from larger spin relaxation length at lower temperatures.

Investigating the effects of noise-estimation errors in simulated cochlear implant speech intelligibility

DEFF Research Database (Denmark)

Kressner, Abigail Anne; May, Tobias; Malik Thaarup Høegh, Rasmus

2017-01-01

A recent study suggested that the most important factor for obtaining high speech intelligibility in noise with cochlear implant recipients is to preserve the low-frequency amplitude modulations of speech across time and frequency by, for example, minimizing the amount of noise in speech gaps....... In contrast, other studies have argued that the transients provide the most information. Thus, the present study investigates the relative impact of these two factors in the framework of noise reduction by systematically correcting noise-estimation errors within speech segments, speech gaps......, and the transitions between them. Speech intelligibility in noise was measured using a cochlear implant simulation tested on normal-hearing listeners. The results suggest that minimizing noise in the speech gaps can substantially improve intelligibility, especially in modulated noise. However, significantly larger...

Aerofoil broadband and tonal noise modelling using stochastic sound sources and incorporated large scale fluctuations

Science.gov (United States)

Proskurov, S.; Darbyshire, O. R.; Karabasov, S. A.

2017-12-01

The present work discusses modifications to the stochastic Fast Random Particle Mesh (FRPM) method featuring both tonal and broadband noise sources. The technique relies on the combination of incorporated vortex-shedding resolved flow available from Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation with the fine-scale turbulence FRPM solution generated via the stochastic velocity fluctuations in the context of vortex sound theory. In contrast to the existing literature, our method encompasses a unified treatment for broadband and tonal acoustic noise sources at the source level, thus, accounting for linear source interference as well as possible non-linear source interaction effects. When sound sources are determined, for the sound propagation, Acoustic Perturbation Equations (APE-4) are solved in the time-domain. Results of the method's application for two aerofoil benchmark cases, with both sharp and blunt trailing edges are presented. In each case, the importance of individual linear and non-linear noise sources was investigated. Several new key features related to the unsteady implementation of the method were tested and brought into the equation. Encouraging results have been obtained for benchmark test cases using the new technique which is believed to be potentially applicable to other airframe noise problems where both tonal and broadband parts are important.

Noise from cooling towers of power parks

International Nuclear Information System (INIS)

Zakaria, J.; Moore, F.K.

1975-01-01

A study is presented of the noise pollution problem for large power parks proposed for the future. Such parks might have an area of about 75 sq. miles, and a generating capacity up to 48000 MW. A comparative analysis has been done for natural and mechanical-draft wet towers as the major sources of acoustic power. Noise radiation from single isolated towers as well as from a dispersed array of towers has been considered for both types of cooling systems. Major noise attenuation effects considered are due to the atmospheric absorption and A-weighting. Conditions of 60F and 70 percent relative humidity in a still atmosphere have been assumed

Noise-induced phase space transport in two-dimensional Hamiltonian systems.

Science.gov (United States)

Pogorelov, I V; Kandrup, H E

1999-08-01

First passage time experiments were used to explore the effects of low amplitude noise as a source of accelerated phase space diffusion in two-dimensional Hamiltonian systems, and these effects were then compared with the effects of periodic driving. The objective was to quantify and understand the manner in which "sticky" chaotic orbits that, in the absence of perturbations, are confined near regular islands for very long times, can become "unstuck" much more quickly when subjected to even very weak perturbations. For both noise and periodic driving, the typical escape time scales logarithmically with the amplitude of the perturbation. For white noise, the details seem unimportant: Additive and multiplicative noise typically have very similar effects, and the presence or absence of a friction related to the noise by a fluctuation-dissipation theorem is also largely irrelevant. Allowing for colored noise can significantly decrease the efficacy of the perturbation, but only when the autocorrelation time, which vanishes for white noise, becomes so large that there is little power at frequencies comparable to the natural frequencies of the unperturbed orbit. Similarly, periodic driving is relatively inefficient when the driving frequency is not comparable to these natural frequencies. This suggests that noise-induced extrinsic diffusion, like modulational diffusion associated with periodic driving, is a resonance phenomenon. The logarithmic dependence of the escape time on amplitude reflects the fact that the time required for perturbed and unperturbed orbits to diverge a given distance scales logarithmically in the amplitude of the perturbation.

Digital signal processing for the Johnson noise thermometry: a time series analysis of the Johnson noise

International Nuclear Information System (INIS)

Moon, Byung Soo; Hwang, In Koo; Chung, Chong Eun; Kwon, Kee Choon; David, E. H.; Kisner, R.A.

2004-06-01

In this report, we first proved that a random signal obtained by taking the sum of a set of signal frequency signals generates a continuous Markov process. We used this random signal to simulate the Johnson noise and verified that the Johnson noise thermometry can be used to improve the measurements of the reactor coolant temperature within an accuracy of below 0.14%. Secondly, by using this random signal we determined the optimal sampling rate when the frequency band of the Johnson noise signal is given. Also the results of our examination on how good the linearity of the Johnson noise is and how large the relative error of the temperature could become when the temperature increases are described. Thirdly, the results of our analysis on a set of the Johnson noise signal blocks taken from a simple electric circuit are described. We showed that the properties of the continuous Markov process are satisfied even when some channel noises are present. Finally, we describe the algorithm we devised to handle the problem of the time lag in the long-term average or the moving average in a transient state. The algorithm is based on the Haar wavelet and is to estimate the transient temperature that has much smaller time delay. We have shown that the algorithm can track the transient temperature successfully

A study of automobile exhaust noise preferences

Science.gov (United States)

Haire, Jay B.; Carney, Melinda J.; Cheenne, Dominique J.

2005-04-01

A study was conducted to investigate the relationship between preferences in automobile exhaust noise and the demographic factors of a listening jury. Noise samples of four different vehicles were recorded at idle as well as at 3000 RPM, and 1/3 octave sound spectra were acquired simultaneously. The recordings were presented to the jury using headphones and a preference survey was administered. Zwicker loudness was computed for all samples. Demographic factors such as gender, age, current and future vehicle ownership, were correlated to listening preferences, and unforeseen results were found, especially in regards to sport utility vehicles (SUV).

Factors Affecting Detection Probability of Acoustic Tags in Coral Reefs

KAUST Repository

Bermudez, Edgar F.

2012-05-01

Acoustic telemetry is an important tool for studying the movement patterns, behaviour, and site fidelity of marine organisms; however, its application is challenged in coral reef environments where complex topography and intense environmental noise interferes with acoustic signals, and there has been less study. Therefore, it is particularly critical in coral reef telemetry studies to first conduct a long-term range test, a tool that provides informa- tion on the variability and periodicity of the transmitter detection range and the detection probability. A one-month range test of a coded telemetric system was conducted prior to a large-scale tagging project investigating the movement of approximately 400 fishes from 30 species on offshore coral reefs in the central Red Sea. During this range test we determined the effect of the following factors on transmitter detection efficiency: distance from receiver, time of day, depth, wind, current, moon-phase and temperature. The experiment showed that biological noise is likely to be responsible for a diel pattern of -on average- twice as many detections during the day as during the night. Biological noise appears to be the most important noise source in coral reefs overwhelming the effect of wind-driven noise, which is important in other studies. Detection probability is also heavily influenced by the location of the acoustic sensor within the reef structure. Understanding the effect of environmental factors on transmitter detection probability allowed us to design a more effective receiver array for the large-scale tagging study.

Measuring of noise emitted by moving vehicles

Directory of Open Access Journals (Sweden)

Skrúcaný Tomáš

2017-01-01

Full Text Available The article aims to measure the intensity of the exterior noise of a vehicle in motion. It provides the results of the measurements of the external noise of selected vehicles in motion and the impact of selected factors on the sound level of driving. There are done two measurements in the paper. Results from the first one are comparing noise level of 9 passenger cars according to the Directive 71/157/EEC. The second one shows the road surface influence on the exterior noise of moving vehicle where the sound level was measured by a road whose surface was made of slightly degraded concrete, and at a different place of the same road, where the surface was renovated by applying asphalt mix onto it.

Low frequency noise in resonant Josephson soliton oscillators

DEFF Research Database (Denmark)

Hansen, Jørn Bindslev; Holst, T.; Wellstood, Frederick C.

1991-01-01

The noise in the resonant soliton mode of long and narrow Josephson tunnel junctions (Josephson transmission lines or JTLs) have been measured in the frequency range from 0.1 Hz to 25 kHz by means of a DC SQUID. The measured white noise was found, to within a factor of two, to be equal...... to the Nyquist voltage noise in a resistance equal to the dynamic resistance RD of the current-voltage characteristic of the bias point. In contrast, measurements of the linewidth of the microwave radiation from the same JTL showed that the spectral density of the underlying noise voltage scaled as R D2/RS where...

Methods of Assessing Noise Nuisance of Real Estate Surroundings

Directory of Open Access Journals (Sweden)

Szopińska Kinga

2016-03-01

Full Text Available Testing what factors create the market value of real estate is key information when preparing property valuations as well as other opinions and professional evaluations on the basis of which court verdicts or administrative decisions are made. One of the factors influencing the value of some real estate is the level of noise present in the surroundings, which can lead to the occurrence of noise nuisance negatively affecting social relations.

Direct-reading dial for noise temperature and noise resistance

DEFF Research Database (Denmark)

Diamond, J.M.

1967-01-01

An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance.......An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance....

Success Factors of Large Scale ERP Implementation in Thailand

OpenAIRE

Rotchanakitumnuai; Siriluck

2010-01-01

The objectives of the study are to examine the determinants of ERP implementation success factors of ERP implementation. The result indicates that large scale ERP implementation success consist of eight factors: project management competence, knowledge sharing, ERP system quality , understanding, user involvement, business process re-engineering, top management support, organization readiness.

The novel phenomenon of noise-catalyzed chaos-order transitions

Energy Technology Data Exchange (ETDEWEB)

Gassmann, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Numerical simulations of the Lorenzian water wheel have been used to investigate the influence of stochastic noise on the lifetime of chaotic transients. Whereas in one region of parameter space no noise dependency could be detected, a shortening of the lifetimes by more than four decades was found in another region. This large effect was produced by a significant modification of the attraction basin of a quasistable stationary state rather than by affecting the chaotic orbits before the chaos-order transition occurred. This novel phenomenon of noise-induced chaos-order transitions is not related to stochastic resonance or other noise-induced effects. (author) 2 figs., 5 refs.

Noise frame duration, masking potency and whiteness of temporal noise.

Science.gov (United States)

Kukkonen, Heljä; Rovamo, Jyrki; Donner, Kristian; Tammikallio, Marja; Raninen, Antti

2002-09-01

Because of the limited contrast range, increasing the duration of the noise frame is often the only option for increasing the masking potency of external, white temporal noise. This, however, reduces the high-frequency cutoff beyond which noise is no longer white. This study was conducted to determine the longest noise frame duration that produces the strongest masking effect and still mimics white noise on the detection of sinusoidal flicker. Contrast energy thresholds (E(th)) were measured for flicker at 1.25 to 20 Hz in strong, purely temporal (spatially uniform), additive, external noise. The masking power of white external noise, characterized by its spectral density at zero frequency N0, increases with the duration of the noise frame. For short noise frame durations, E(th) increased in direct proportion to N0, keeping the nominal signal-to-noise ratio [SNR = (E(th)/N0)(0.5)] constant at threshold. The masking effect thus increased with the duration of the noise frame and the noise mimicked white noise. When noise frame duration and N0 increased further, the nominal SNR at threshold started to decrease, indicating that noise no longer mimicked white noise. The minimum number of noise frames per flicker cycle needed to mimic white noise decreased with increasing flicker frequency from 8.3 at 1.25 Hz to 1.6 at 20 Hz. The critical high-frequency cutoff of detection-limiting temporal noise in terms of noise frames per signal cycle depends on the temporal frequency of the signal. This is opposite to the situation in the spatial domain and must be taken into consideration when temporal signals are masked with temporal noise.

Effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.

Science.gov (United States)

Crino, Ondi L; Johnson, Erin E; Blickley, Jessica L; Patricelli, Gail L; Breuner, Creagh W

2013-06-01

Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species.

Hearing aid noise suppression and working memory function

DEFF Research Database (Denmark)

Neher, Tobias; Wagener, Kirsten C.; Fischer, Rosa-Linde

2018-01-01

OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading......-to-noise ratio (SNR) improvement. Auditory working memory was assessed at +6 dB SNR using listening span and N-back paradigms. STUDY SAMPLE: Twenty experienced HA users ages 55-80 with large differences in reading span. RESULTS: For the listening span measurements, there was an influence of HA setting....... CONCLUSIONS: HA noise suppression may affect the recognition and recall of speech at positive SNRs, irrespective of individual reading span. Future work should improve the reliability of the auditory working memory measurements....

Noise impact assessment of wind farms

International Nuclear Information System (INIS)

Hayes, M.

1993-01-01

The noise impact assessment of a wind farm is dependent upon a number of factors pertinent to the site. The most controversial is the selection of a criterion which is acceptable to both the developer of a site, in terms of maximising the number of turbines he may operate without fear of injunction to stop, and the local residents and Environmental Health Officer who will have to enforce any agreements. A number of British Standards exist which cover noise issues. There are, however, certain reservations about their use when applied to potential wind farm developments; some of the more relevant standards are outlined. In addition, Draft Planning Guidance notes which have recently been issued are discussed. These are intended to provide an indication to local planning authorities as to what noise levels and criteria may be acceptable when considering noise emitted by wind farms. No European standard for noise emission from wind farms exists but the legislative position in Denmark, the Netherlands, Germany and Sweden is briefly considered. It is considered that when a maximum level criterion is set it should take into account the existing background noise levels based on measurements which are taken at the most sensitive dwellings to the site. A method for calculating emitted noise levels from turbine arrays is described. (UK)

Spatial learning and memory deficits in young adult mice exposed to a brief intense noise at postnatal age

Institute of Scientific and Technical Information of China (English)

Shan Tao; Lijie Liu; Lijuan Shi; Xiaowei Li; Pei Shen; Qingying Xun; Xiaojing Guo; Zhiping Yu; Jian Wang

2015-01-01

Noise pollution is a major hazardous factor to human health and is likely harmful for vulnerable groups such as pre-term infants under life-support system in an intensive care unit. Previous studies have suggested that noise exposure impairs children's learning ability and cognitive performance and cognitive functions in animal models in which the effect is mainly attributed to the oxidant stress of noise on the cognitive brain. The potential role of noise induced hearing loss (NIHL), rather than the oxidant stress, has also been indicated by a depression of neurogenesis in the hippocampus long after a brief noise exposure, which produces only a tentative oxidant stress. It is not clear if noise exposure and NIHL during early development exerts a long term impact on cognitive function and neurogenesis towards adulthood. In the present study, a brief noise exposure at high sound level was performed in neonatal C57BL/6J mice (15 days after birth) to produce a significant amount of permanent hearing loss as proved 2 months after the noise. At this age, the noise-exposed animals showed deteriorated spatial learning and memory abilities and a reduction of hippocampal neurogenesis as compared with the control. The averaged hearing threshold was found to be strongly correlated with the scores for spatial learning and memory. We consider the effects observed are largely due to the loss of hearing sensitivity, rather than the oxidant stress, due to the long interval between noise exposure and the observations.

LNA A 1.9 GHZ low noise amplifier

Directory of Open Access Journals (Sweden)

Jorge Julián Moreno-Rubio

2006-12-01

Full Text Available This paper shows the design, the simulation, and the layout from a low noise amplifier (LNA, designed with and approximate band from 25 to 80 MHz. The design results of the matching neworks are shown, its noise figure, its available and transduced gain according to its non lineal model (TOM, the DC network, crash inductors and matching capacitors with the large impedance transmission lines.

Quantum Noise Reduction with Pulsed Light in Optical Fibers.

Science.gov (United States)

Bergman, Keren

Optical fibers offer considerable advantages over bulk nonlinear media for the generation of squeezed states. This thesis reports on experimental investigations of reducing quantum noise by means of squeezing in nonlinear fiber optic interferometers. Fibers have low insertion loss which allows for long interaction lengths. High field intensities are easily achieved in the small cores of single mode fibers. Additionally, the nonlinear process employed is self phase modulation or the Kerr effect, whose broad band nature requires no phase matching and can be exploited with ultra-short pulses of high peak intensity. All these advantageous features of fibers result in easily obtained large nonlinear phase shifts and subsequently large squeezing parameters. By the self phase modulation process a correlation is produced between the phase and amplitude fluctuations of the optical field. The attenuated or squeezed quadrature has a lower noise level than the initial level associated with the coherent state field before propagation. The resulting reduced quantum noise quadrature can be utilized to improve the sensitivity of a phase measuring instrument such as an interferometer. Because the Kerr nonlinearity is a degenerate self pumping process, the squeezed noise is at the same frequency as the pump field. Classical pump noise can therefore interfere with the desired measurement of the quantum noise reduction. The most severe noise process is the phase noise caused by thermally induced index modulation of the fiber. This noise termed Guided Acoustic Wave Brillouin Scattering, or GAWBS, by previous researchers is studied and analyzed. Experiments performed to overcome GAWBS successfully with several schemes are described. An experimental demonstration of an interferometric measurement with better sensitivity than the standard quantum limit is described. The results lead to new understandings into the limitations of quantum noise reduction that can be achieved in the

Active noise control in a duct to cancel broadband noise

Science.gov (United States)

Chen, Kuan-Chun; Chang, Cheng-Yuan; Kuo, Sen M.

2017-09-01

The paper presents cancelling duct noises by using the active noise control (ANC) techniques. We use the single channel feed forward algorithm with feedback neutralization to realize ANC. Several kinds of ducts noises including tonal noises, sweep tonal signals, and white noise had investigated. Experimental results show that the proposed ANC system can cancel these noises in a PVC duct very well. The noise reduction of white noise can be up to 20 dB.

Solution to selected occupational health problems in the operation of large machinery in potash mines

Energy Technology Data Exchange (ETDEWEB)

Stuhrmann, D.

1979-01-01

This paper discusses health hazards, such as noise, vibrations and air pollution caused by the operation of large machines and their effect on the human body. Means of reducing the influence of these factors are: improved ear protection against noise, special gymnastics at the end of each shift, warm water swimming and a weekly sauna treatment for the effects of vibrations. Air pollution caused by diesel engines is monitored. Engine exhaust standards are examined in detail and methods are proposed to further reduce air pollution.

Effect of noise in computed tomographic reconstructions on detectability

International Nuclear Information System (INIS)

Hanson, K.M.

1982-01-01

The detectability of features in an image is ultimately limited by the random fluctuations in density or noise present in that image. The noise in CT reconstructions arising from the statistical fluctuations in the one-dimensional input projection measurements has an unusual character owing to the reconstruction procedure. Such CT image noise differs from the white noise normally found in images in its lack of low-frequency components. The noise power spectrum of CT reconstructions can be related to the effective density of x-ray quanta detected in the projection measurements, designated as NEQ (noise-equivalent quanta). The detectability of objects that are somewhat larger than the spatial resolution is directly related to NEQ. Since contrast resolution may be defined in terms of the ability to detect large, low-contrast objects, the measurement of a CT scanner's NEQ may be used to characterize its contrast sensitivity

Effect of noise on the standard mapping

International Nuclear Information System (INIS)

Karney, C.F.F.; Rechester, A.B.; White, R.B.

1981-03-01

The effect of a small amount of noise on the standard mapping is considered. Whenever the standard mapping possesses accelerator models (where the action increases approximately linearly with time), the diffusion coefficient contains a term proportional to the reciprocal of the variance of the noise term. At large values of the stochasticity parameter, the accelerator modes exhibit a universal behavior. As a result the dependence of the diffusion coefficient on stochasticity parameter also shows some universal behavior

Core Noise: Overview of Upcoming LDI Combustor Test

Science.gov (United States)

Hultgren, Lennart S.

2012-01-01

This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Fixed Wing Project. The presentation covers: the emerging importance of core noise due to turbofan design trends and its relevance to the NASA N+3 noise-reduction goal; the core noise components and the rationale for the current emphasis on combustor noise; and the current and planned research activities in the combustor-noise area. Two NASA-sponsored research programs, with particular emphasis on indirect combustor noise, "Acoustic Database for Core Noise Sources", Honeywell Aerospace (NNC11TA40T) and "Measurement and Modeling of Entropic Noise Sources in a Single-Stage Low-Pressure Turbine", U. Illinois/U. Notre Dame (NNX11AI74A) are briefly described. Recent progress in the development of CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is outlined. Combustor-design trends and the potential impacts on combustor acoustics are discussed. A NASA GRC developed nine-point lean-direct-injection (LDI) fuel injector is briefly described. The modification of an upcoming thermo-acoustic instability evaluation of the GRC injector in a combustor rig to also provide acoustic information relevant to community noise is presented. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Quiet Performance Research Theme of the Fixed Wing Project aims to develop concepts and technologies to dramatically reduce the perceived community noise attributable to aircraft with minimal impact on weight and performance.

Noise-induced phase space transport in two-dimensional Hamiltonian systems

International Nuclear Information System (INIS)

Pogorelov, I.V.; Kandrup, H.E.

1999-01-01

First passage time experiments were used to explore the effects of low amplitude noise as a source of accelerated phase space diffusion in two-dimensional Hamiltonian systems, and these effects were then compared with the effects of periodic driving. The objective was to quantify and understand the manner in which open-quotes stickyclose quotes chaotic orbits that, in the absence of perturbations, are confined near regular islands for very long times, can become open-quotes unstuckclose quotes much more quickly when subjected to even very weak perturbations. For both noise and periodic driving, the typical escape time scales logarithmically with the amplitude of the perturbation. For white noise, the details seem unimportant: Additive and multiplicative noise typically have very similar effects, and the presence or absence of a friction related to the noise by a fluctuation-dissipation theorem is also largely irrelevant. Allowing for colored noise can significantly decrease the efficacy of the perturbation, but only when the autocorrelation time, which vanishes for white noise, becomes so large that there is little power at frequencies comparable to the natural frequencies of the unperturbed orbit. Similarly, periodic driving is relatively inefficient when the driving frequency is not comparable to these natural frequencies. This suggests that noise-induced extrinsic diffusion, like modulational diffusion associated with periodic driving, is a resonance phenomenon. The logarithmic dependence of the escape time on amplitude reflects the fact that the time required for perturbed and unperturbed orbits to diverge a given distance scales logarithmically in the amplitude of the perturbation. copyright 1999 The American Physical Society

Stochastic resonance: noise-enhanced order

International Nuclear Information System (INIS)

Anishchenko, Vadim S; Neiman, Arkady B; Moss, F; Shimansky-Geier, L

1999-01-01

Stochastic resonance (SR) provides a glaring example of a noise-induced transition in a nonlinear system driven by an information signal and noise simultaneously. In the regime of SR some characteristics of the information signal (amplification factor, signal-to-noise ratio, the degrees of coherence and of order, etc.) at the output of the system are significantly improved at a certain optimal noise level. SR is realized only in nonlinear systems for which a noise-intensity-controlled characteristic time becomes available. In the present review the physical mechanism and methods of theoretical description of SR are briefly discussed. SR features determined by the structure of the information signal, noise statistics and properties of particular systems with SR are studied. A nontrivial phenomenon of stochastic synchronization defined as locking of the instantaneous phase and switching frequency of a bistable system by external periodic force is analyzed in detail. Stochastic synchronization is explored in single and coupled bistable oscillators, including ensembles. The effects of SR and stochastic synchronization of ensembles of stochastic resonators are studied both with and without coupling between the elements. SR is considered in dynamical and nondynamical (threshold) systems. The SR effect is analyzed from the viewpoint of information and entropy characteristics of the signal, which determine the degree of order or self-organization in the system. Applications of the SR concept to explaining the results of a series of biological experiments are discussed. (reviews of topical problems)

Stochastic resonance: noise-enhanced order

Energy Technology Data Exchange (ETDEWEB)

Anishchenko, Vadim S; Neiman, Arkady B [N.G. Chernyshevskii Saratov State University, Saratov (Russian Federation); Moss, F [Department of Physics and Astronomy, University of Missouri at St. Louis (United States); Shimansky-Geier, L [Humboldt University at Berlin (Germany)

1999-01-31

Stochastic resonance (SR) provides a glaring example of a noise-induced transition in a nonlinear system driven by an information signal and noise simultaneously. In the regime of SR some characteristics of the information signal (amplification factor, signal-to-noise ratio, the degrees of coherence and of order, etc.) at the output of the system are significantly improved at a certain optimal noise level. SR is realized only in nonlinear systems for which a noise-intensity-controlled characteristic time becomes available. In the present review the physical mechanism and methods of theoretical description of SR are briefly discussed. SR features determined by the structure of the information signal, noise statistics and properties of particular systems with SR are studied. A nontrivial phenomenon of stochastic synchronization defined as locking of the instantaneous phase and switching frequency of a bistable system by external periodic force is analyzed in detail. Stochastic synchronization is explored in single and coupled bistable oscillators, including ensembles. The effects of SR and stochastic synchronization of ensembles of stochastic resonators are studied both with and without coupling between the elements. SR is considered in dynamical and nondynamical (threshold) systems. The SR effect is analyzed from the viewpoint of information and entropy characteristics of the signal, which determine the degree of order or self-organization in the system. Applications of the SR concept to explaining the results of a series of biological experiments are discussed. (reviews of topical problems)

Swept-sine noise-induced damage as a hearing loss model for preclinical assays

Directory of Open Access Journals (Sweden)

Lorena eSanz

2015-02-01

Full Text Available Mouse models are key tools for studying cochlear alterations in noise-induced hearing loss and for evaluating new therapies. Stimuli used to induce deafness in mice are usually white and octave band noises that include very low frequencies, considering the large mouse auditory range. We designed different sound stimuli, enriched in frequencies up to 20 kHz (violet noises to examine their impact on hearing thresholds and cochlear cytoarchitecture after short exposure. In addition, we developed a cytocochleogram to quantitatively assess the ensuing structural degeneration and its functional correlation. Finally, we used this mouse model and cochleogram procedure to evaluate the potential therapeutic effect of transforming growth factor β1 inhibitors P17 and P144 on noise-induced hearing loss. CBA mice were exposed to violet swept-sine noise with different frequency ranges (2-20 or 9-13 kHz and levels (105 or 120 dB SPL for 30 minutes. Mice were evaluated by auditory brainstem response and otoacoustic emission tests prior to and 2, 14 and 28 days after noise exposure. Cochlear pathology was assessed with gross histology; hair cell number was estimated by a stereological counting method. Our results indicate that functional and morphological changes induced by violet swept-sine noise depend on the sound level and frequency composition. Partial hearing recovery followed the exposure to 105 dB SPL, whereas permanent cochlear damage resulted from the exposure to 120 dB SPL. Exposure to 9-13 kHz noise caused an auditory threshold shift in those frequencies that correlated with hair cell loss in the corresponding areas of the cochlea that were spotted on the cytocochleogram. In summary, we present mouse models of noise-induced hearing loss, which depending on the sound properties of the noise, cause different degrees of cochlear damage, and could therefore be used to study molecules which are potential players in hearing loss protection and repair.

Road Traffic Noise Exposure in Gothenburg 1975-2010.

Directory of Open Access Journals (Sweden)

Mikael Ögren

Full Text Available Traffic noise exposure within a city varies over time and space. In this study, we developed a modified noise calculation method and used this method together with population and traffic data to estimate the time trend of noise exposure for the population in Gothenburg, Sweden, from 1975 to 2010. The noise calculation method was based on the standard Nordic method for road traffic noise with modifications using area-level statistics for population and building structures instead of precise geocoding of each inhabitant. Noise emission per vehicle was assumed to be constant over the period. The results show an increase in noise exposure over time. The number of inhabitants exposed at an equivalent level above 55 dB increased from 93000 to 146000 inhabitants between 1975 and 2010, and the percentage of the population exposed at this level increased from 22% to 29% over the same period. Traffic increase (1.4% per year and population increase/concentration (0.50% per year were approximately equally important factors behind this increase in exposure.

Cardiovascular effects of environmental noise: Research in Germany

Directory of Open Access Journals (Sweden)

Christian Maschke

2011-01-01

Full Text Available Research on systematic noise effects started in Germany back in the fifties with basic experimental studies on humans. As a result, noise was classified as a non-specific stressor, which could cause an ergotropic activation of the complete organism. In the light of this background research a hypothesis was proposed that long-term noise exposure could have an adverse effect on health. This hypothesis was further supported by animal studies. Since the sixties, the adverse effects of chronic road traffic noise exposure were further examined in humans with the help of epidemiological studies. More epidemiological aircraft noise studies followed in the 1970s and thereafter. The sample size was increased, relevant confounding factors were taken into account, and the exposure and health outcomes were investigated objectively and with higher quality measures. To date, more than 20 German epidemiological traffic noise studies have focused on noise-induced health effects, mainly on the cardiovascular system. In particular, the newer German noise studies demonstrate a clear association between residential exposure to traffic noise (particularly night noise and cardiovascular outcomes. Nevertheless, additional research is needed, particularly on vulnerable groups and multiple noise exposures. The epidemiological findings have still not been fully considered in German regulations, particularly for aircraft noise. The findings, however, were taken into account in national recommendations. The Federal Environment Agency recommends noise rating levels of 65 dB(A for the day and 55 dB(A for the night, as a short-term goal. In the medium term, noise rating levels of 60 / 50 (day, night should be reached and noise rating levels of 55 / 45 in the long run.

Potential of neuro-fuzzy methodology to estimate noise level of wind turbines

Science.gov (United States)

Nikolić, Vlastimir; Petković, Dalibor; Por, Lip Yee; Shamshirband, Shahaboddin; Zamani, Mazdak; Ćojbašić, Žarko; Motamedi, Shervin

2016-01-01

Wind turbines noise effect became large problem because of increasing of wind farms numbers since renewable energy becomes the most influential energy sources. However, wind turbine noise generation and propagation is not understandable in all aspects. Mechanical noise of wind turbines can be ignored since aerodynamic noise of wind turbine blades is the main source of the noise generation. Numerical simulations of the noise effects of the wind turbine can be very challenging task. Therefore in this article soft computing method is used to evaluate noise level of wind turbines. The main goal of the study is to estimate wind turbine noise in regard of wind speed at different heights and for different sound frequency. Adaptive neuro-fuzzy inference system (ANFIS) is used to estimate the wind turbine noise levels.

The effects of noise exposure and musical training on suprathreshold auditory processing and speech perception in noise.

Science.gov (United States)

Yeend, Ingrid; Beach, Elizabeth Francis; Sharma, Mridula; Dillon, Harvey

2017-09-01

Recent animal research has shown that exposure to single episodes of intense noise causes cochlear synaptopathy without affecting hearing thresholds. It has been suggested that the same may occur in humans. If so, it is hypothesized that this would result in impaired encoding of sound and lead to difficulties hearing at suprathreshold levels, particularly in challenging listening environments. The primary aim of this study was to investigate the effect of noise exposure on auditory processing, including the perception of speech in noise, in adult humans. A secondary aim was to explore whether musical training might improve some aspects of auditory processing and thus counteract or ameliorate any negative impacts of noise exposure. In a sample of 122 participants (63 female) aged 30-57 years with normal or near-normal hearing thresholds, we conducted audiometric tests, including tympanometry, audiometry, acoustic reflexes, otoacoustic emissions and medial olivocochlear responses. We also assessed temporal and spectral processing, by determining thresholds for detection of amplitude modulation and temporal fine structure. We assessed speech-in-noise perception, and conducted tests of attention, memory and sentence closure. We also calculated participants' accumulated lifetime noise exposure and administered questionnaires to assess self-reported listening difficulty and musical training. The results showed no clear link between participants' lifetime noise exposure and performance on any of the auditory processing or speech-in-noise tasks. Musical training was associated with better performance on the auditory processing tasks, but not the on the speech-in-noise perception tasks. The results indicate that sentence closure skills, working memory, attention, extended high frequency hearing thresholds and medial olivocochlear suppression strength are important factors that are related to the ability to process speech in noise. Crown Copyright © 2017. Published by

Sounds and Noises. A Position Paper on Noise Pollution.

Science.gov (United States)

Chapman, Thomas L.

This position paper focuses on noise pollution and the problems and solutions associated with this form of pollution. The paper is divided into the following five sections: Noise and the Ear, Noise Measurement, III Effects of Noise, Acoustics and Action, and Programs and Activities. The first section identifies noise and sound, the beginnings of…

[Factors influencing electrocardiogram results in workers exposed to noise in steel-making and steel-rolling workshops of an iron and steel plant].

Science.gov (United States)

Li, Y H; Yu, S F; Gu, G Z; Chen, G S; Zhou, W H; Wu, H; Jiao, J

2016-02-20

To investigate the factors influencing the electrocardiogram results in the workers exposed to noise in steel-making and steel rolling workshops of an iron and steel plant. From September to December, 2013, cluster sampling was used to select 3 150 workers exposed to noise in the steel-making and steel-rolling workshops of an iron and steel plant, and a questionnaire survey and physical examinations were performed. The number of valid workers was 2 915, consisting of 1 606 workers in the steel-rolling workshop and 1 309 in the steel-making workshop. The electrocardiogram results of the workers in steel-making and steel-rolling workshops were analyzed. The overall abnormal rate of electrocardiogram was 26.35%, and the workers in the steel-making workshop had a significantly higher abnormal rate of electrocardiogram than those in the steel-rolling workshop(32.24% vs 21.54%, Pelectrocardiogram than female workers(27.59% vs 18.61%, Pelectrocardiogram than those who did not drink(28.17% vs 23.75%, Pelectrocardiogram than those who were not exposed to high temperature(29.43% vs 20.14%, Pelectrocardiogram in the workers with cumulative noise exposure levels of electrocardiogram results. High cumulative noise exposure, alcohol consumption, and high temperature may affect the abnormal rate of electrocardiogram in the workers exposed to noise in steel-making and steel-rolling workshops.

Soundscape elaboration from anthrophonic adaptation of community noise

Science.gov (United States)

Teddy Badai Samodra, FX

2018-03-01

Under the situation of an urban environment, noise has been a critical issue in affecting the indoor environment. A reliable approach is required for evaluation of the community noise as one factor of anthrophonic in the urban environment. This research investigates the level of noise exposure from different community noise sources and elaborates the advantage of the noise disadvantages for soundscape innovation. Integrated building element design as a protector for noise control and speech intelligibility compliance using field experiment and MATLAB programming and modeling are also carried out. Meanwhile, for simulation analysis and building acoustic optimization, Sound Reduction-Speech Intelligibility and Reverberation Time are the main parameters for identifying tropical building model as case study object. The results show that the noise control should consider its integration with the other critical issue, thermal control, in an urban environment. The 1.1 second of reverberation time for speech activities and noise reduction more than 28.66 dBA for critical frequency (20 Hz), the speech intelligibility index could be reached more than fair assessment, 0.45. Furthermore, the environmental psychology adaptation result “Close The Opening” as the best method in high noise condition and personal adjustment as the easiest and the most adaptable way.

The continuing Exposure to Noise in Workers in the Society and Living Environment

Directory of Open Access Journals (Sweden)

Shahrokh Ehtesham zadeh

1999-03-01

Full Text Available As the industry develops in the societies, human being is more likely to exposed to high level of noises and be at risk of hearing loss. Urbanism and working in the situation which are not in accordance with the personal nature make people even more susceptible to risk factors of hearing loss. Exposure of workers to industrial noise has been the subject to several studies and it seems that reconsidering the situations in both society and nature can be a key to change environment for decreasing noise in the society.For example in Tehran, geographically, the slope of the earth from north to south is 5-10% which is a main factor contributing in noise pollution.Moreover, the source of most outdoor noise worldwide is mainly construction and transportation systems including motor vehicles, air craft noises and rail noises. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.In the current article we have examined both conditions in the hearing condition of workers with high levels of noise exposure.

Exploring Technostress: Results of a Large Sample Factor Analysis

OpenAIRE

Jonušauskas, Steponas; Raišienė, Agota Giedrė

2016-01-01

With reference to the results of a large sample factor analysis, the article aims to propose the frame examining technostress in a population. The survey and principal component analysis of the sample consisting of 1013 individuals who use ICT in their everyday work was implemented in the research. 13 factors combine 68 questions and explain 59.13 per cent of the answers dispersion. Based on the factor analysis, questionnaire was reframed and prepared to reasonably analyze the respondents’ an...

Low-noise, transformer-coupled resonant photodetector for squeezed state generation.

Science.gov (United States)

Chen, Chaoyong; Shi, Shaoping; Zheng, Yaohui

2017-10-01

In an actual setup of squeezed state generation, the stability of a squeezing factor is mainly limited by the performance of the servo-control system, which is mainly influenced by the shot noise and gain of a photodetector. We present a unique transformer-coupled LC resonant amplifier as a photodetector circuit to reduce the electronic noise and increase the gain of the photodetector. As a result, we obtain a low-noise, high gain photodetector with the gain of more than 1.8×10 5 V/A, and the input current noise of less than 4.7 pA/Hz. By adjusting the parameters of the transformer, the quality factor Q of the resonant circuit is close to 100 in the frequency range of more than 100 MHz, which meets the requirement for weak power detection in the application of squeezed state generation.

Optimization of sensitivity and noise in piezoresistive cantilevers

DEFF Research Database (Denmark)

Yu, Xiaomei; Thaysen, Jacob; Hansen, Ole

2002-01-01

In this article, the sensitivity and the noise of piezoresistive cantilevers were systematically investigated with respect to the piezoresistor geometry, the piezoresistive materials, the doping dose, the annealing temperature, and the operating biased voltage. With the noise optimization results......(-6), the biggest gauge factors was 95, and the minimum detectable deflection (MDD) at 6 V and 200 Hz-measurement bandwidth was 0.3 nm for a single-crystal silicon cantilever. Of the two LPCVD silicon piezoresistive cantilevers, amorphous silicon piezoresistors had relatively lower 1/f noise. The MDD for a LPCVD...

Flicker-noise Spectroscopy In Earthquake Prediction Research

Science.gov (United States)

Desherevsky, A. V.; Lukk, A. A.; Sidorin, A. Y.; Timashev, S. F.

It has been found out that a two-component model including a seasonal and a flicker- noise components occurs to be a more adequate model of statistical structure of time series of long-term geophysical observations' data. Unlike a white noise which sig- nifies absence of any relation between the system's current dynamics and past events in it, presence of flicker-noise indicates that such a relation in the system does ex- ist. Flicker-noise pertains a property of scale invariance. It seems natural to relate self-similarity of statistical properties of geophysical parameters' variations on dif- ferent scales to self-similar (fractal) properties of geophysical medium. At the same time self-similar time variations of geophysical parameters may indicate to presence of deterministic chaos in geophysical system's evolution. An important element of a proposed approach is application of stochastic models of preparation of each concrete large seismic event. Instead of regular, for example bay-form precursor variations, occurrence of precursors of another kind associated in particular with variation in parameter fluctuations should be expected. To solve a problem of large earthquakes prediction we use Flicker-Noise Spectroscopy (FNS) as a basis of a new approach proposed by us. The basis of the FNS methodology is a postulate about the impor- tant information significance of sequences of various dynamic irregularities (bursts or spikes, jumps with different characteristic values, discontinuities of derivatives) of the measured temporal, spatial and energetic variables on each level of hierarchical orga- nization of studied systems. A proposed new method using integral values of analyzed signals - power spectra and different moments ("structural functions") of a different order as information relations, has demonstrated principally new opportunities in a search of large earthquake precursors already at a preliminary stage of some data analysis. This research was supported by

Effects of Vehicle Weight and True Versus Indicated Airspeed on BVI Noise During Steady Descending Flight

Science.gov (United States)

Stephenson, James H.; Greenwood, Eric

2015-01-01

Blade-vortex interaction noise measurements are analyzed for an AS350B helicopter operated at 7000 ft elevation above sea level. Blade-vortex interaction (BVI) noise from four, 6 degree descent conditions are investigated with descents flown at 80 knot true and indicated airspeed, as well as 4400 and 3915 pound take-off weights. BVI noise is extracted from the acquired acoustic signals by way of a previously developed time-frequency analysis technique. The BVI extraction technique is shown to provide a better localization of BVI noise, compared to the standard Fourier transform integration method. Using this technique, it was discovered that large changes in BVI noise amplitude occurred due to changes in vehicle gross weight. Changes in BVI noise amplitude were too large to be due solely to changes in the vortex strength caused by varying vehicle weight. Instead, it is suggested that vehicle weight modifies the tip-path-plane angle of attack, as well as induced inflow, resulting in large variations of BVI noise. It was also shown that defining flight conditions by true airspeed, rather than indicated airspeed, provides more consistent BVI noise signals.

[Noise Effects on Mental Health: a review of literature].

Science.gov (United States)

Makopa Kenda, Israel; Agoub, Mohamed; Ahami, A O T

2014-01-01

Any human activity generates noise. It is considered as a risk factor for people's health. The present review of literature has assessed the impact of noise on mental health; it is summarized into four points: objective, methods, results and conclusion. The main objective of this study is to expose the actual knowledge state of noise effects on mental health after overview and critical analysis of literature to identify the acquired and shortcomings, to reflect on research direction in terms of noise pollution in the future. The literature review was conducted based on: research of keys words in articles published, research of the number of quotations of articles in Journal Citation Reports (JCR), published in web of science, research of impact factor of journals. One hundred articles were selected, after analyzing contents, items were classified into: fundamental studies (25%), experimental studies (50%), and epidemiological studies (25%). The fundamental studies have verified the hypothesis according to which noise generates stress. Researchers have dosed hormones of stress in plasma, urine and saliva in individuals exposed to noise of different decibels. The results found were unanimous: The rates of stress hormones found, were significantly high in three liquids. This means that noise causes stress. For experimental studies, researchers have experienced the role of noise on memory, attention and performance. Human subjects were exposed to different decibels to assess level of disruption to their memory, attention, and performance. The results revealed that noise disturbs memory, distracts attention and decreases performance. Experimental studies are the most abundant and constitute 50% of the current literature review.The epidemiological studies have evaluated the intellectual performance of students in schools located in noisy environments and residents in areas surrounding airports, railways and highways. RESULTS have revealed that students in schools located

Strong negative self regulation of Prokaryotic transcription factors increases the intrinsic noise of protein expression

Directory of Open Access Journals (Sweden)

Jenkins Dafyd J

2008-01-01

Full Text Available Abstract Background Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. Results We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Conclusion Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic

Preconditioner-free Wiener filtering with a dense noise matrix

Science.gov (United States)

Huffenberger, Kevin M.

2018-05-01

This work extends the Elsner & Wandelt (2013) iterative method for efficient, preconditioner-free Wiener filtering to cases in which the noise covariance matrix is dense, but can be decomposed into a sum whose parts are sparse in convenient bases. The new method, which uses multiple messenger fields, reproduces Wiener-filter solutions for test problems, and we apply it to a case beyond the reach of the Elsner & Wandelt (2013) method. We compute the Wiener-filter solution for a simulated Cosmic Microwave Background (CMB) map that contains spatially varying, uncorrelated noise, isotropic 1/f noise, and large-scale horizontal stripes (like those caused by atmospheric noise). We discuss simple extensions that can filter contaminated modes or inverse-noise-filter the data. These techniques help to address complications in the noise properties of maps from current and future generations of ground-based Microwave Background experiments, like Advanced ACTPol, Simons Observatory, and CMB-S4.

A hybrid, broadband, low noise charge preamplifier for simultaneous high resolution energy and time information with large capacitance semiconductor detector

International Nuclear Information System (INIS)

Goyot, M.

1975-05-01

A broadband and low noise charge preamplifier was developed in hybrid form, for a recoil spectrometer requiring large capacitance semiconductor detectors. This new hybrid and low cost preamplifier permits good timing information without compromising energy resolution. With a 500 pF external input capacity, it provides two simultaneous outputs: (i) the faster, current sensitive, with a rise time of 9 nsec and 2 mV/MeV on 50 ohms load, (ii) the lower, charge sensitive, with an energy resolution of 14 keV (FWHM Si) using a RC-CR ungated filter of 2 μsec and a FET input protection [fr

The influence of Room Acoustic Aspects on the Noise Exposure of Symphonic Orchestra Musicians

NARCIS (Netherlands)

Wenmaekers, R.H.C.; Hak, C.C.J.M.; Luxemburg, van L.C.J.

2011-01-01

Musicians in a symphonic orchestra are exposed to the noise of a large number of different sound sources. The noise exposure can vary largely and has many aspects of influence. One group of aspects are musical aspects, like the orchestra size and composition, the musical piece and its interpretation

Integers without large prime factors in short intervals: Conditional ...

Indian Academy of Sciences (India)

α > 0 the interval (X, X +. √. X(log X)1/2+o(1)] contains an integer having no prime factor exceeding Xα for all X sufficiently large. Keywords. Smooth numbers; Riemann zeta function. 1. Introduction. Suppose P (n) denotes the largest prime factor of an integer n > 1 and let us declare. P(1) = 1. Given a positive real number y, ...

Noise exposure under hyperbaric conditions

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-03-01

Objective evidence exists that divers demonstrate a hearing deficit greater than would be expected from ageing effects alone. Deafness in divers may be caused by a number of factors other than exposure to excessive noise levels, eg barotrauma, ear infection etc. This review concentrates on the concern that exposure of commercial divers to noise while at work may cause a hearing deficit. Sound pressure levels recorded both underwater and in diving chambers often exceed those allowable to workers onshore. However, the sound perceived by the diver is modified both in amplitude and in frequency when he is either underwater or in pressurised chambers. Broadly the effect of this modification is to attenuate the sound and thus offer some protection from high noise levels. The degree of attentuation varies with the frequency of the sound, however it is also possible under specific conditions associated with gas density for the sensitivity to particular frequencies to be amplified above that for normal atmospheric air. The levels of sound observed from some underwater tools are of concern even after allowing for a significant de-sensitisation of the divers` hearing. Reports of tinnitus and temporary hearing loss following a dive are sure signs that the noise levels have been harmful. It is not possible at present to describe risk criteria for hearing damage due to noise exposure associated with diving. (author)

Risk assessment of influence factors on occupational hearing loss in noise – exposed workers in typical metal industry

Directory of Open Access Journals (Sweden)

Farhadian Maryam

2014-11-01

Full Text Available Background & Objectives : Worker exposure conditions such as noise level, exposure duration, use of hearing protection devices and health behaviors are commonly related to noise induced hearing loss. The objective of this study was risk assessment of influence factors on occupational hearing loss in noise exposed workers in typical noisy process . Methods : Information about occupational exposure of seventy workers employed in a noisy press workshop was gathered using the standard questionnaire. Audiometery test was performed using the screening audiometer (Model-Mevox. Afterward, the collected data was analyzed by using the Cox model in SPSS software. Results : Based on results of the developed model, the job type and using status of HPD were most important features to induce hearing loss among workers. The risk of hearing loss among workers with the intermittent use of hearing protection was 3.1 times more than workers used their devices continuously. Relative risk of hearing loss among smoker workers compared with non-smoker was 1.1. Conclusion : The developed model could determine the effects of workers’ exposure conditions on risk of occupational hearing loss. This systematic approach can be considered as a helpful tool for determination the effectiveness of hearing conservation program and provide useful information for the managers and professionals in order to revise the existing health programs.

Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise

NARCIS (Netherlands)

Salomons, E.M.; Janssen, S.A.

2011-01-01

In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a

Hearing loss in the elderly: History of occupational noise exposure.

Science.gov (United States)

Meneses-Barriviera, Caroline Luiz; Melo, Juliana Jandre; Marchiori, Luciana Lozza de Moraes

2013-04-01

 Noise exposure is one of the most common health risk factors, and workers are exposed to sound pressure levels capable of producing hearing loss.  To assess the prevalence of hearing loss in the elderly and its possible association with a history of occupational noise exposure and with sex.  A prospective study in subjects aged over 60 years. The subjects underwent anamnesis and audiological assessment. The Mann-Whitney test and multiple logistic regression, with 95% confidence interval and p hearing I (500, 1000, and 2000 Hz p = 0.8318) and the mean hearing II (3000, 4000, and 6000 Hz; p occupational noise exposure, we obtained the medium hearing I (p = 0.9542) and the mean hearing II (p = 0.0007).  There was a statistically significant association between hearing loss at high frequencies and the risk factors being male and occupational noise exposure.

Effects of a traffic noise background on judgements of aircraft noise

Science.gov (United States)

Powell, C. A.; Rice, C. G.

1974-01-01

A study was conducted in which subjects judged aircraft noises in the presence of road traffic background noise. Two different techniques for presenting the background noises were evaluated. For one technique, the background noise was continuous over the whole of a test session. For the other, the background noise was changed with each aircraft noise. A range of aircraft noise levels and traffic noise levels were presented to simulate typical indoor levels.

Occupational noise-induced tinnitus: does it affect workers' quality of life?

Science.gov (United States)

Muluk, Nuray Bayar; Oguztürk, Omer

2008-02-01

This prospective study aimed to investigate the quality of life of workers in a steel factory. The study group was composed of 16 male workers with tinnitus and 30 ears. Fifteen male workers without tinnitus and 30 ears were included into the control group. Workers were evaluated by questionnaire, pure-tone audiometry, and the SF-36 Health Survey. In the study group, tinnitus loudness levels (TLLs) were found. In the study group, the domains general mental health and role limitations owing to emotional problems were significantly lower than in the control group. Older age, industrial noise exposure over a long period, higher noise exposure during work, and hearing loss secondary to occupational noise caused workers to experience higher TLLs. Earheadings protected workers more than earplugs, and TLLs were lower. Important factors that affect workers' quality of life are maximum exposed noise levels, daily and total noise exposure time, and exposure to continuous noise. Occupational noise-induced tinnitus mainly causes emotional disability rather than physical disability. Emotionally impaired QOL results may be due to tinnitus-related psychological problems. Workers should have knowledge about the hazardous effects of noise. Periodic health checkups and regular seminars have great importance. Workers must be aware of other ototoxic factors, such as medications and noisy music. In the future, researchers should develop a screening method to detect those with a more hereditary affinity to hearing loss.

Evaluation of noise pollution in oil extracting region of Lavan and the effect of noise enclosure on noise abatement

Directory of Open Access Journals (Sweden)

F. Golbabaei

2007-09-01

Full Text Available Background and aims   Overexposure to industrial noise pollution induce hearing loss workers. Occupational hearing loss may cause interference whit oral communication, so it may  increase the risk of occupational accidents in workplace as well as affects whit social activities.  This study was conducted on Lavan Island, are of oil extracting regions in the south of Iran. The  object of this study was to evaluate noise pollution and determining the effect of noise enclosure  on noise abatement.   Methods   The noise sources were recognized and noise pressure level was measured by CEL- 440. Noise dose of the exposed workers in high level noise area were measured by CEL 272.   Results   Major noise sources were gas turbines, diesel generators, compressors, fans and gas containing pips, noise contour map revealers that noise level were higher than the recommended national exposure limit. The results of workers noise dose show that their noise exposure were  higher than the recommended value, (p<0.001. Finally, by using the results of noise frequency  analysis of different noise sources, the noise pressure level of each sources was determined in   terms of enclosing them.   Conclusion   By enclosing the noise sources, noise pressure levels can be lowered douse to  acceptable levels but limitation of applying enclosure should be regarded.  

Noise cancellation properties of displacement noise free interferometer

International Nuclear Information System (INIS)

Sato, Shuichi; Kawamura, Seiji; Nishizawa, Atsushi; Chen Yanbei

2010-01-01

We have demonstrated the practical feasibility of a displacement- and frequency-noise-free laser interferometer (DFI) by partially implementing a recently proposed optical configuration using bi-directional Mach-Zehnder interferometers (MZIs). The noise cancellation efficiency was evaluated by comparing the displacement noise spectrum of the MZIs and the DFI, demonstrating up to 50 dB of noise cancellation. In addition, the possible extension of DFI as QND device is explored.

Energy-Based Wavelet De-Noising of Hydrologic Time Series

Science.gov (United States)

Sang, Yan-Fang; Liu, Changming; Wang, Zhonggen; Wen, Jun; Shang, Lunyu

2014-01-01

De-noising is a substantial issue in hydrologic time series analysis, but it is a difficult task due to the defect of methods. In this paper an energy-based wavelet de-noising method was proposed. It is to remove noise by comparing energy distribution of series with the background energy distribution, which is established from Monte-Carlo test. Differing from wavelet threshold de-noising (WTD) method with the basis of wavelet coefficient thresholding, the proposed method is based on energy distribution of series. It can distinguish noise from deterministic components in series, and uncertainty of de-noising result can be quantitatively estimated using proper confidence interval, but WTD method cannot do this. Analysis of both synthetic and observed series verified the comparable power of the proposed method and WTD, but de-noising process by the former is more easily operable. The results also indicate the influences of three key factors (wavelet choice, decomposition level choice and noise content) on wavelet de-noising. Wavelet should be carefully chosen when using the proposed method. The suitable decomposition level for wavelet de-noising should correspond to series' deterministic sub-signal which has the smallest temporal scale. If too much noise is included in a series, accurate de-noising result cannot be obtained by the proposed method or WTD, but the series would show pure random but not autocorrelation characters, so de-noising is no longer needed. PMID:25360533

Hearing aid noise suppression and working memory function

DEFF Research Database (Denmark)

Neher, Tobias; Wagener, Kirsten C.; Fischer, Rosa-Linde

2018-01-01

OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading......-to-noise ratio (SNR) improvement. Auditory working memory was assessed at +6 dB SNR using listening span and N-back paradigms. STUDY SAMPLE: Twenty experienced HA users ages 55-80 with large differences in reading span. RESULTS: For the listening span measurements, there was an influence of HA setting...... on sentence-final word recognition and recall, with the directional microphones leading to ~6% better performance than the single-channel noise reduction. For the N-back measurements, there was substantial test-retest variability and no influence of HA setting. No interactions with reading span were found...

A Health-Based Metric for Evaluating the Effectiveness of Noise Barrier Mitigation Associated With Transport Infrastructure Noise

Directory of Open Access Journals (Sweden)

Geoffrey P Prendergast

2017-01-01

Full Text Available Introduction: This study examines the use of the number of night-time sleep disturbances as a health-based metric to assess the cost effectiveness of rail noise mitigation strategies for situations, wherein high-intensity noises dominate such as freight train pass-bys and wheel squeal. Materials and Methods: Twenty residential properties adjacent to the existing and proposed rail tracks in a noise catchment area of the Epping to Thornleigh Third Track project were used as a case study. Awakening probabilities were calculated for individual’s awakening 1, 3 and 5 times a night when subjected to 10 independent freight train pass-by noise events using internal maximum sound pressure levels (LAFmax. Results: Awakenings were predicted using a random intercept multivariate logistic regression model. With source mitigation in place, the majority of the residents were still predicted to be awoken at least once per night (median 88.0%, although substantial reductions in the median probabilities of awakening three and five times per night from 50.9 to 29.4% and 9.2 to 2.7%, respectively, were predicted. This resulted in a cost-effective estimate of 7.6–8.8 less people being awoken at least three times per night per A$1 million spent on noise barriers. Conclusion: The study demonstrates that an easily understood metric can be readily used to assist making decisions related to noise mitigation for large-scale transport projects.

Noise data management using commercially available data-base software

International Nuclear Information System (INIS)

Damiano, B.; Thie, J.A.

1988-01-01

A data base has been created using commercially available software to manage the data collected by an automated noise data acquisition system operated by Oak Ridge National Laboratory at the Fast Flux Test Facility (FFTF). The data base was created to store, organize, and retrieve selected features of the nuclear and process signal noise data, because the large volume of data collected by the automated system makes manual data handling and interpretation based on visual examination of noise signatures impractical. Compared with manual data handling, use of the data base allows the automatically collected data to be utilized more fully and effectively. The FFTF noise data base uses the Oracle Relational Data Base Management System implemented on a desktop personal computer

Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals

Directory of Open Access Journals (Sweden)

Sebastián Pantoja

2009-08-01

Full Text Available The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network.

Qualitative criteria and thresholds for low noise asphalt mixture design

Science.gov (United States)

Vaitkus, A.; Andriejauskas, T.; Gražulytė, J.; Šernas, O.; Vorobjovas, V.; Kleizienė, R.

2018-05-01

Low noise asphalt pavements are cost efficient and cost effective alternative for road traffic noise mitigation comparing with noise barriers, façade insulation and other known noise mitigation measures. However, design of low noise asphalt mixtures strongly depends on climate and traffic peculiarities of different regions. Severe climate regions face problems related with short durability of low noise asphalt mixtures in terms of considerable negative impact of harsh climate conditions (frost-thaw, large temperature fluctuations, hydrological behaviour, etc.) and traffic (traffic loads, traffic volumes, studded tyres, etc.). Thus there is a need to find balance between mechanical and acoustical durability as well as to ensure adequate pavement skid resistance for road safety purposes. Paper presents analysis of the qualitative criteria and design parameters thresholds of low noise asphalt mixtures. Different asphalt mixture composition materials (grading, aggregate, binder, additives, etc.) and relevant asphalt layer properties (air void content, texture, evenness, degree of compaction, etc.) were investigated and assessed according their suitability for durable and effective low noise pavements. Paper concluded with the overview of requirements, qualitative criteria and thresholds for low noise asphalt mixture design for severe climate regions.

Studying the Noise Control Engineering Protocols in Industry

Directory of Open Access Journals (Sweden)

Hamid Golshah

1999-03-01

Full Text Available Today, sound is one of the detrimental factors in the workplace and its harmful impact has been so important that scientists have named it “Noise Pollutions”. Hearing is one of the five senses of human being which is also a medium for communicating with other s and enjoying the pleasant feeling of listening to a piece of music. In spite of this, changes in the intensity and frequency of sound can make it annoying. Using Sound Level Meter to measure the dB of noise in the workplace and noise control principles will be discussed here.

Noise And Charge Transport In Carbon Nanotube Devices

Science.gov (United States)

Reza, Shahed; Huynh, Quyen T.; Bosman, Gijs; Sippel, Jennifer; Rinzler, Andrew G.

2005-11-01

The charge transport and noise properties of three terminal, gated devices containing multiple, single wall, metallic and semiconductor carbon nanotubes have been measured as a function of gate and drain bias at 300K. Using pulsed bias the metallic tubes could be burned sequentially enabling the separation of measured conductance and low frequency excess noise into metallic and semiconductor contributions. The relative low frequency excess noise of the metallic tubes was about a factor 100 lower than that of the semiconductor tubes, whereas the conductance of the metallic tubes was significantly higher (10 to 50 times) than that of the semiconductor tubes.

Masking potency and whiteness of noise at various noise check sizes.

Science.gov (United States)

Kukkonen, H; Rovamo, J; Näsänen, R

1995-02-01

The masking effect of spatial noise can be increased by increasing either the rms contrast or check size of noise. In this study, the authors investigated the largest noise check size that still mimics the effect of white noise in grating detection and how it depends on the bandwidth and spatial frequency of a grating. The authors measured contrast energy thresholds, E, for vertical cosine gratings at various spatial frequencies and bandwidths. Gratings were embedded in two-dimensional spatial noise. The side length of the square noise checks was varied in the experiments. The spectral density, N(0,0), of white spatial noise at zero frequency was calculated by multiplying the noise check area by the rms contrast of noise squared. The physical signal-to-noise ratio at threshold [E/N(0,0)]0.5 was initially constant but then started to decrease. The largest noise check that still produced a constant physical signal-to-noise ratio at threshold was directly proportional to the spatial frequency. When expressed as a fraction of grating cycle, the largest noise check size depended only on stimulus bandwidth. The smallest number of noise checks per grating cycle needed to mimic the effect of white noise decreased from 4.2 to 2.6 when the number of grating cycles increased from 1 to 64. Spatial noise can be regarded as white in grating detection if there are at least four square noise checks per grating cycle at all spatial frequencies.

Study of the intrinsic background noise of a quadrupole mass spectrometer

International Nuclear Information System (INIS)

Sysoev, A.A.; Islamov, I.M.; Khafizov, R.S.

1977-01-01

A proper background noise of a quadrupole mass-spectrometer is studied. The main sources of the noise have been analysed as well as their contributions to the overall noise of the device. It is shown that the main contribution is made by the photocurrent of the first dynode of the secondary-electron multiplier from ultraviolet radiation. The construction of the detecting system of the mass-spectrometer is given allowing one to increase the signal-to-noise ratio by a factor of > 500

Unexpected role of excess noise in spontaneous emission

International Nuclear Information System (INIS)

Lamprecht, C.; Ritsch, H.

2002-01-01

A single inverted two-level atom is used as a theoretical model for a quantum noise detector to investigate fundamental properties of excess noise in an unstable optical resonator. For a symmetric unstable spherical mirror cavity, we develop an analytic quantum description of the field in terms of a complete set of normalizable biorthogonal quasimodes and adjoint modes. Including the interaction with a single two-level atom leads to a description analogous to the Jaynes-Cummings model with modified coupling constants. One finds a strong position and geometry-dependent atomic decay probability proportional to the square root √(K) of the excess noise factor K at the cavity center. Introducing an additional homogeneous gain one recovers the K-fold emission enhancement that has been predicted before for the linewidth of an unstable cavity laser. We find that excess noise may be viewed as a spatial redistribution of the field quantum noise inside the resonator. Taking a position average of the atomic decay rate over the cavity volume leads to a cancellation of the excess noise enhancement

Characterization and Impact of Low Frequency Wind Turbine Noise Emissions

Science.gov (United States)

Finch, James

Wind turbine noise is a complex issue that requires due diligence to minimize any potential impact on quality of life. This study enhances existing knowledge of wind turbine noise through focused analyses of downwind sound propagation, directionality, and the low frequency component of the noise. Measurements were conducted at four wind speeds according to a design of experiments at incremental distances and angles. Wind turbine noise is shown to be highly directional, while downwind sound propagation is spherical with limited ground absorption. The noise is found to have a significant low frequency component that is largely independent of wind speed over the 20-250 Hz range. The generated low frequency noise is shown to be audible above 40 Hz at the MOE setback distance of 550 m. Infrasound levels exhibit higher dependency on wind speed, but remain below audible levels up to 15 m/s.

The Role that Natural Environment Plays in Reducing Noise Pollution

Directory of Open Access Journals (Sweden)

Nasim Saber Maash

1999-03-01

Full Text Available Noise pollution is one of the major problems for the present time and it can affect the life of human being. Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life. Researchers have mentioned a lot of devastating effects of noise that can disrupt the physical and psychological health of human beings. Noise pollution has also been considered as an important issue which needs to be solved in industrial countries and also as a main factor that is required to be minimized in factory construction and also in producing machinery. In the current article we are aimed at discussing some solutions that natural environment can bring to mankind regarding the reduction of noise pollution.

Correction factors for clinical dosemeters used in large field dosimetry

International Nuclear Information System (INIS)

Campos, L.L.; Caldas, L.

1989-08-01

The determination of the absorbed dose in high-energy photon and electron beams by the user is carried out as a two-step procedure. First the ionization chamber is calibrated at a reference quality by the user at a standard laboratory, and then the chamber is used to determine the absorbed dose with the user's beam. A number of conversion and correction factors have to be applied. Different sets of factors are needed depending on the physical quantity the calibration refers to, the calibration geometry and the chamber design. Another correction factor to be introduced for the absorbed dose determination in large fields refers to radiation effects on the stem, cable and sometimes connectors. A simple method was developed to be suggested to hospital physicists to be followed during large radiation field dosimetry, in order to evaluate the radiation effects of cables and connectors and to determine correction factors for each system or geometry. (author) [pt

Non-Markovian noise

International Nuclear Information System (INIS)

Fulinski, A.

1994-01-01

The properties of non-Markovian noises with exponentially correlated memory are discussed. Considered are dichotomic noise, white shot noise, Gaussian white noise, and Gaussian colored noise. The stationary correlation functions of the non-Markovian versions of these noises are given by linear combinations of two or three exponential functions (colored noises) or of the δ function and exponential function (white noises). The non-Markovian white noises are well defined only when the kernel of the non-Markovian master equation contains a nonzero admixture of a Markovian term. Approximate equations governing the probability densities for processes driven by such non-Markovian noises are derived, including non-Markovian versions of the Fokker-Planck equation and the telegrapher's equation. As an example, it is shown how the non-Markovian nature changes the behavior of the driven linear process

Noise Exposure and Hearing Loss Among Sand and Gravel Miners

OpenAIRE

Landen, Deborah; Wilkins, Steve; Stephenson, Mark; McWilliams, Linda

2004-01-01

The objectives of this study were to describe workplace noise exposures, risk factors for hearing loss, and hearing levels among sand and gravel miners, and to determine whether full shift noise exposures resulted in changes in hearing thresholds from baseline values. Sand and gravel miners (n = 317) were interviewed regarding medical history, leisure-time and occupational noise exposure, other occupational exposures, and use of hearing protection. Audiometric tests were performed both before...

Feasibility of Johnson Noise Thermometry based on Digital Signal Processing Techniques

International Nuclear Information System (INIS)

Hwang, In Koo; Kim, Yang Mo

2014-01-01

This paper presents an implementation strategy of noise thermometry based on a digital signal processing technique and demonstrates its feasibilities. A key factor in its development is how to extract the small thermal noise signal from other noises, for example, random noise from amplifiers and continuous electromagnetic interference from the environment. The proposed system consists of two identical amplifiers and uses a cross correlation function to cancel the random noise of the amplifiers. Then, the external interference noises are eliminated by discriminating the difference in the peaks between the thermal signal and external noise. The gain of the amplifiers is estimated by injecting an already known pilot signal. The experimental simulation results of signal processing methods have demonstrated that the proposed approach is an effective method in eliminating an external noise signal and performing gain correction for development of the thermometry

Sleep, noise and health: Review

Directory of Open Access Journals (Sweden)

Mia Zaharna

2010-01-01

Full Text Available Sleep is a physiologic recuperative state that may be negatively affected by factors such as psychosocial and work stress as well as external stimuli like noise. Chronic sleep loss is a common problem in today′s society, and it may have significant health repercussions such as cognitive impairment, and depressed mood, and negative effects on cardiovascular, endocrine, and immune function. This article reviews the definition of disturbed sleep versus sleep deprivation as well as the effects of noise on sleep. We review the various health effects of chronic partial sleep loss with a focus on the neuroendocrine/hormonal, cardiovascular, and mental health repercussions.

Prevalence of occupational noise induced hearing loss amongst traffic police personnel

OpenAIRE

Singh, V K; Mehta, A K

1999-01-01

Traffic branch personnel of Pune traffic police were screened for presence of noise induced hearing loss. A very significant number (81.2%) showed sensorineural hearing loss. The various factors responsible for noise induced hearing loss are discussed.

Measuring the Noise Caused by Tehran Metro

Directory of Open Access Journals (Sweden)

Majid Abbas Pour

1999-03-01

Full Text Available One of the most common and important sources of noise in the residential environments are vehicles such as airplanes and subways. Trafficking of vehicles in streets and highways, psychologically, have damaging impacts on people living close to such areas. The development and expansion of the trading and industrial units is another factor that causes more and more exposure to noise.We have aimed at measuring the noises caused by vibration of subways of the Line of Karaj-Tehran-Mehrshahr and its effect on its surrounding area.To study this effect we designed a mathematical model and put the information of this subway line in the mentioned model. Then we analyzed the findings.This model demonstrated that we can control the harsh noise of the subway by reducing the speed of the train to 60Km/h in some points and increase in other parts to 130Km/h.

Population coding in mouse visual cortex: response reliability and dissociability of stimulus tuning and noise correlation

Directory of Open Access Journals (Sweden)

Jorrit S. Montijn

2014-06-01

Full Text Available The primary visual cortex is an excellent model system for investigating how neuronal populations encode information, because of well-documented relationships between stimulus characteristics and neuronal activation patterns. We used two-photon calcium imaging data to relate the performance of different methods for studying population coding (population vectors, template matching, and Bayesian decoding algorithms to their underlying assumptions. We show that the variability of neuronal responses may hamper the decoding of population activity, and that a normalization to correct for this variability may be of critical importance for correct decoding of population activity. Second, by comparing noise correlations and stimulus tuning we find that these properties have dissociated anatomical correlates, even though noise correlations have been previously hypothesized to reflect common synaptic input. We hypothesize that noise correlations arise from large non-specific increases in spiking activity acting on many weak synapses simultaneously, while neuronal stimulus response properties are dependent on more reliable connections. Finally, this paper provides practical guidelines for further research on population coding and shows that population coding cannot be approximated by a simple summation of inputs, but is heavily influenced by factors such as input reliability and noise correlation structure.

Operational modeling of dose and noise for computed tomography in a pediatric hospital

International Nuclear Information System (INIS)

Miller Clemente, Rafael A.; Perez Diaz, Marlen; Mora Reyes, Yudel; Rodriguez Garlobo, Maikel; Castillo Salazar, Rafael

2008-01-01

Noise becomes a critical factor in Computed Tomography (CT) because most detailed applications on soft tissue show a low contrast nature. Noise establishes an inferior limit to the contrast detectable by the observer. Various pixel noise models had been devised taking into account operational parameters on Single and Multi Detector Slice CT. The aim of this work was to obtain a predictive operational model for image noise addressed to pediatric protocols, taking into account scanning factors with a Single Slice CT unit dedicated to pediatric applications. A multiple linear regression model is proposed to predict noise in images of uniform phantoms equivalent to head and abdomen. A model for reported volumetric Computed Tomography Dose Index (CTDI VOL ) was obtained too for tradeoffs analysis approaching optimization purposes in pediatric applications. Eight independent variables were considered: phantom diameter, reconstruction mode, tube current, tube kVp, collimation, Field of View (FOV), reconstruction filter, and post processing filter. Results show good agreement with measurements, with adjusted coefficients of multiple determination of 0.936 and 0.744 for noise and CTDI VOL models respectively. Tube current, object diameter, collimation and reconstruction filters were the most influencing variables. The model application contributes to identify each factor's influence enhancing the operational possibilities approaching optimization of noise and dose tradeoffs. Acceptable noise levels and optimization strategies can be devised from models obtained towards lower tube current values combined with greater slice thickness and kVp taking into account the doses to pediatric patients. (author)

Road traffic and cardiovascular health effects - Road traffic noise and air pollution

NARCIS (Netherlands)

Kluizenaar, Y. de; Miedema, H.M.E.

2009-01-01

Exposure to both environmental noise and air pollution has been associated with cardiovascular health effects. Until now, few studies have considered both stressors simultaneously. Two large studies were carried out investigating the relationship between road traffic noise and several cardiovascular

Natural and man-made terrestrial electromagnetic noise: an outlook

Directory of Open Access Journals (Sweden)

A. Meloni

2007-06-01

Full Text Available The terrestrial environment is continuously exposed to electromagnetic radiations which set up a «background» electromagnetic noise. Within the Non Ionizing Radiation band (NIR, i.e. for frequencies lower than 300 GHz, this background can have a natural or an artificial origin. Natural origins of electromagnetic radiations are generally atmospheric or cosmic while artificial origins are technological applications, power transmission, communications, etc. This paper briefly describes the natural and man-made electromagnetic noise in the NIR band. Natural noise comes from a large variety of sources involving different physical phenomena and covering a wide range of frequencies and showing various propagation characteristics with an extremely broad range of power levels. Due to technological growth man-made electromagnetic noise is nowadays superimposed on natural noise almost everywhere on Earth. In the last decades man-made noise has increased dramatically over and above the natural noise in residential and business areas. This increase has led some scientists to consider possible negative effects of electromagnetic waves on human life and living systems in general. Accurate measurements of natural and man-made electromagnetic noise are necessary to understand the relative power levels in the different bands and their influence on life.

Noise-induced annoyance from transportation noise: short-term responses to a single noise source in a laboratory.

Science.gov (United States)

Kim, Jaehwan; Lim, Changwoo; Hong, Jiyoung; Lee, Soogab

2010-02-01

An experimental study was performed to compare the annoyances from civil-aircraft noise, military-aircraft noise, railway noise, and road-traffic noise. Two-way within-subjects designs were applied in this research. Fifty-two subjects, who were naive listeners, were given various stimuli with varying levels through a headphone in an anechoic chamber. Regardless of the frequency weighting network, even under the same average energy level, civil-aircraft noise was the most annoying, followed by military-aircraft noise, railway noise, and road-traffic noise. In particular, penalties in the time-averaged, A-weighted sound level (TAL) of about 8, 5, and 5 dB, respectively, were found in the civil-aircraft, military-aircraft, and railway noises. The reason could be clarified through the high-frequency component and the variability in the level. When people were exposed to sounds with the same maximum A-weighted level, a railway bonus of about 3 dB was found. However, transportation noise has been evaluated by the time-averaged A-weighted level in most countries. Therefore, in the present situation, the railway bonus is not acceptable for railway vehicles with diesel-electric engines.

Convergence Improvement of Response Matrix Method with Large Discontinuity Factors

International Nuclear Information System (INIS)

Yamamoto, Akio

2003-01-01

In the response matrix method, a numerical divergence problem has been reported when extremely small or large discontinuity factors are utilized in the calculations. In this paper, an alternative response matrix formulation to solve the divergence problem is discussed, and properties of iteration matrixes are investigated through eigenvalue analyses. In the conventional response matrix formulation, partial currents between adjacent nodes are assumed to be discontinuous, and outgoing partial currents are converted into incoming partial currents by the discontinuity factor matrix. Namely, the partial currents of the homogeneous system (i.e., homogeneous partial currents) are treated in the conventional response matrix formulation. In this approach, the spectral radius of an iteration matrix for the partial currents may exceed unity when an extremely small or large discontinuity factor is used. Contrary to this, an alternative response matrix formulation using heterogeneous partial currents is discussed in this paper. In the latter approach, partial currents are assumed to be continuous between adjacent nodes, and discontinuity factors are directly considered in the coefficients of a response matrix. From the eigenvalue analysis of the iteration matrix for the one-group, one-dimensional problem, the spectral radius for the heterogeneous partial current formulation does not exceed unity even if an extremely small or large discontinuity factor is used in the calculation; numerical stability of the alternative formulation is superior to the conventional one. The numerical stability of the heterogeneous partial current formulation is also confirmed by the two-dimensional light water reactor core analysis. Since the heterogeneous partial current formulation does not require any approximation, the converged solution exactly reproduces the reference solution when the discontinuity factors are directly derived from the reference calculation

New large-Nc relations for the electromagnetic nucleon-to-Δ form factors

International Nuclear Information System (INIS)

Vladimir Pascalutsa; Marc Vanderhaeghen

2006-01-01

We establish relations which express the three N → Δ transition form factors in terms of the nucleon form factors. These relations are based on the known large-N c relation between the N → Δ electric quadrupole moment and the neutron charge radius, and a newly derived large-N c relation between the electric quadrupole (E2) and Coulomb quadrupole (C2) transitions. Namely, in the large-N c limit we find C2=E2. We show that these relations provide predictions for the N → Δ electromagnetic form factors which are found to be in very good agreement with experiment for moderate momentum transfers. They also provide constraints for the N → Δ GPDs

A Novel Recurrent Neural Network for Manipulator Control With Improved Noise Tolerance.

Science.gov (United States)

Li, Shuai; Wang, Huanqing; Rafique, Muhammad Usman

2017-04-12

In this paper, we propose a novel recurrent neural network to resolve the redundancy of manipulators for efficient kinematic control in the presence of noises in a polynomial type. Leveraging the high-order derivative properties of polynomial noises, a deliberately devised neural network is proposed to eliminate the impact of noises and recover the accurate tracking of desired trajectories in workspace. Rigorous analysis shows that the proposed neural law stabilizes the system dynamics and the position tracking error converges to zero in the presence of noises. Extensive simulations verify the theoretical results. Numerical comparisons show that existing dual neural solutions lose stability when exposed to large constant noises or time-varying noises. In contrast, the proposed approach works well and has a low tracking error comparable to noise-free situations.

Noise pollution in iron and steel industry

International Nuclear Information System (INIS)

Bisio, G.; Piromalli, W.; Acerbo, P.

1999-01-01

Iron and steel industry is characterized by high energy consumption and thus present remarkable problems from the point of view of noise pollution. The aims of this paper is to examine characteristic and acoustical emissions and immisions of some fundamentals iron and steel plants with several remarks on the possible measures to reduce noise pollution. For a large integrate iron and steel system, some surveys are shown with all devices running and, in addition, comparisons are made with other surveys when the main devices were out of service owing to great maintenance works [it

Impact of noise and air pollution on pregnancy outcomes.

Science.gov (United States)

Gehring, Ulrike; Tamburic, Lillian; Sbihi, Hind; Davies, Hugh W; Brauer, Michael

2014-05-01

Motorized traffic is an important source of both air pollution and community noise. While there is growing evidence for an adverse effect of ambient air pollution on reproductive health, little is known about the association between traffic noise and pregnancy outcomes. We evaluated the impact of residential noise exposure on small size for gestational age, preterm birth, term birth weight, and low birth weight at term in a population-based cohort study, for which we previously reported associations between air pollution and pregnancy outcomes. We also evaluated potential confounding of air pollution effects by noise and vice versa. Linked administrative health data sets were used to identify 68,238 singleton births (1999-2002) in Vancouver, British Columbia, Canada, with complete covariate data (sex, ethnicity, parity, birth month and year, income, and education) and maternal residential history. We estimated exposure to noise with a deterministic model (CadnaA) and exposure to air pollution using temporally adjusted land-use regression models and inverse distance weighting of stationary monitors for the entire pregnancy. Noise exposure was negatively associated with term birth weight (mean difference = -19 [95% confidence interval = -23 to -15] g per 6 dB(A)). In joint air pollution-noise models, associations between noise and term birth weight remained largely unchanged, whereas associations decreased for all air pollutants. Traffic may affect birth weight through exposure to both air pollution and noise.

Scalable tensor factorizations for incomplete data

DEFF Research Database (Denmark)

Acar, Evrim; Dunlavy, Daniel M.; KOlda, Tamara G.

2011-01-01

to factorize data sets with missing values with the goal of capturing the underlying latent structure of the data and possibly reconstructing missing values (i.e., tensor completion). We focus on one of the most well-known tensor factorizations that captures multi-linear structure, CANDECOMP/PARAFAC (CP...... experiments, our algorithm is shown to successfully factorize tensors with noise and up to 99% missing data. A unique aspect of our approach is that it scales to sparse large-scale data, e.g., 1000 × 1000 × 1000 with five million known entries (0.5% dense). We further demonstrate the usefulness of CP...

Low-Frequency Noise in High-T Superconductor Josephson Junctions, Squids, and Magnetometers.

Science.gov (United States)

Miklich, Andrew Hostetler

The design and performance of high-T_ {rm c} dc superconducting quantum interference devices (SQUIDs), the junctions that comprise them, and magnetometers made from them are described, with special attention paid to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDs. This noise suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions, in contrast, have levels of critical current noise that are controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5times 10^{-30} J Hz^ {-1} at 1 Hz is reported. Magnetometers in which a (9 mm)^2 pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz^{-1/2} down to frequencies below 1 Hz, improving to 39 fT Hz^{-1/2} at 1 Hz with the addition of a 50 mm-diameter single-turn flux transformer. Although the performance of these devices is sufficient for single -channel biomagnetometry or geophysical studies, their relatively poor coupling to the pickup loop makes it difficult to satisfy the competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz^{-1/2} in the white noise region is reported with a (10 mm) ^2 pickup loop. However, additional 1/f noise from the processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz^ {-1/2}. High-T_{ rm c} SQUIDs are shown to exhibit additional 1/f noise when they are cooled in a nonzero static magnetic field because of the additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05 mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution

Effect of flow parameters on flare stack generator noise

International Nuclear Information System (INIS)

Dinn, T.S.

1998-01-01

The SoundPLAN Computer Noise Model was used to determine the general effect of flare noise in a community adjacent to a petrochemical plant. Tests were conducted to determine the effect of process flow conditions and the pulsating flame on the flare stack generator noise from both a refinery flare and process flare. Flaring under normal plant operations, the flaring of fuel gas and the flaring of hydrogen were the three conditions that were tested. It was shown that the steam flow rate was the determining factor in the flare stack generated noise. Variations in the water seal level in the flare line surge tank increased or decreased the gas flowrate, which resulted in a pulsating flame. The period and amplitude of the pulsating noise from the flare stacks was determined by measuring several parameters. Flare stack noise oscillations were found to be greater for the process flare than for the refinery flare stack. It was suggested that minimizing the amount of steam fed to the flare and improving the burner design would minimize noise. 2 tabs., 6 figs

Environmental noise and noise modelling-some aspects in Malaysian development

International Nuclear Information System (INIS)

Leong, Mohd Salman; Mohd Shafiek bin Hj Yaacob

1994-01-01

Environmental noise is of growing concern in Malaysia with the increasing awareness of the need for an environmental quality consistent with improved quality of life. While noise is one of the several elements in an Environmental Impact Assessment report, the degree of emphasis in the assessment is not as thorough as other aspects in the EIA study. The measurements, prediction (if at all any), and evaluation tended to be superficial. The paper presents a summary of correct noise descriptors and annoyance assessment parameters appropriate for the evaluation of environmental noise. The paper further highlights current inadequacies in the Environmental Quality Act for noise pollution, and annoyance assessment. Some examples of local noise pollution are presented. A discussion on environmental noise modelling is presented. Examples illustrating environmental noise modelling for a mining operation and a power station are given. It is the authors' recommendation that environmental noise modelling be made mandatory in all EIA studies such that a more definitive assessment could be realised

Noise detection in heart sound recordings.

Science.gov (United States)

Zia, Mohammad K; Griffel, Benjamin; Fridman, Vladimir; Saponieri, Cesare; Semmlow, John L

2011-01-01

Coronary artery disease (CAD) is the leading cause of death in the United States. Although progression of CAD can be controlled using drugs and diet, it is usually detected in advanced stages when invasive treatment is required. Current methods to detect CAD are invasive and/or costly, hence not suitable as a regular screening tool to detect CAD in early stages. Currently, we are developing a noninvasive and cost-effective system to detect CAD using the acoustic approach. This method identifies sounds generated by turbulent flow through partially narrowed coronary arteries to detect CAD. The limiting factor of this method is sensitivity to noises commonly encountered in the clinical setting. Because the CAD sounds are faint, these noises can easily obscure the CAD sounds and make detection impossible. In this paper, we propose a method to detect and eliminate noise encountered in the clinical setting using a reference channel. We show that our method is effective in detecting noise, which is essential to the success of the acoustic approach.

Simple programmable voltage reference for low frequency noise measurements

Science.gov (United States)

Ivanov, V. E.; Chye, En Un

2018-05-01

The paper presents a circuit design of a low-noise voltage reference based on an electric double-layer capacitor, a microcontroller and a general purpose DAC. A large capacitance value (1F and more) makes it possible to create low-pass filter with a large time constant, effectively reducing low-frequency noise beyond its bandwidth. Choosing the optimum value of the resistor in the RC filter, one can achieve the best ratio between the transient time, the deviation of the output voltage from the set point and the minimum noise cut-off frequency. As experiments have shown, the spectral density of the voltage at a frequency of 1 kHz does not exceed 1.2 nV/√Hz the maximum deviation of the output voltage from the predetermined does not exceed 1.4 % and depends on the holding time of the previous value. Subsequently, this error is reduced to a constant value and can be compensated.

Neurally based measurement and evaluation of environmental noise

CERN Document Server

Soeta, Yoshiharu

2015-01-01

This book deals with methods of measurement and evaluation of environmental noise based on an auditory neural and brain-oriented model. The model consists of the autocorrelation function (ACF) and the interaural cross-correlation function (IACF) mechanisms for signals arriving at the two ear entrances. Even when the sound pressure level of a noise is only about 35 dBA, people may feel annoyed due to the aspects of sound quality. These aspects can be formulated by the factors extracted from the ACF and IACF. Several examples of measuring environmental noise—from outdoor noise such as that of aircraft, traffic, and trains, and indoor noise such as caused by floor impact, toilets, and air-conditioning—are demonstrated. According to the noise measurement and evaluation, applications for sound design are discussed. This book provides an excellent resource for students, researchers, and practitioners in a wide range of fields, such as the automotive, railway, and electronics industries, and soundscape, architec...

Annoyance of low frequency noise and traffic noise

DEFF Research Database (Denmark)

Mortensen, F.R.; Poulsen, Torben

2001-01-01

The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

Noise minimization in eukaryotic gene expression.

Directory of Open Access Journals (Sweden)

Hunter B Fraser

2004-06-01

Full Text Available All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or "noise." Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection.

Noise minimization in eukaryotic gene expression

Energy Technology Data Exchange (ETDEWEB)

Fraser, Hunter B.; Hirsh, Aaron E.; Giaever, Guri; Kumm, Jochen; Eisen, Michael B.

2004-01-15

All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or noise. Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection.

Noise minimization in eukaryotic gene expression

International Nuclear Information System (INIS)

Fraser, Hunter B.; Hirsh, Aaron E.; Giaever, Guri; Kumm, Jochen; Eisen, Michael B.

2004-01-01

All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or noise. Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection

Noise level in neonatal incubators: A comparative study of three models.

Science.gov (United States)

Fernández Zacarías, F; Beira Jiménez, J L; Bustillo Velázquez-Gaztelu, P J; Hernández Molina, R; Lubián López, Simón

2018-04-01

Preterm infants usually have to spend a long time in an incubator, excessive noise in which can have adverse physiological and psychological effects on neonates. In fact, incubator noise levels typically range from 45 to 70 dB but differences in this respect depend largely on the noise measuring method used. The primary aim of this work was to assess the extent to which noise in an incubator comes from its own fan and how efficiently the incubator can isolate external noise. Three different incubator models were characterized for acoustic performance by measuring their internal noise levels in an anechoic chamber, and also for noise isolation efficiency by using a pink noise source in combination with an internal and an external microphone that were connected to an SVAN958 noise analyzer. The incubators studied produced continuous equivalent noise levels of 53.5-58 dB and reduced external noise by 5.2-10.4 dB. A preterm infant in an incubator is exposed to noise levels clearly exceeding international recommendations even though such levels usually comply with the limit set in the standard IEC60601-2-19: 2009 (60 dBA) under normal conditions of use. Copyright © 2018. Published by Elsevier B.V.

An aerodynamic noise propagation model for wind turbines

DEFF Research Database (Denmark)

Zhu, Wei Jun; Sørensen, Jens Nørkær; Shen, Wen Zhong

2005-01-01

A model based on 2-D sound ray theory for aerodynamic noise propagation from wind turbine rotating blades is introduced. The model includes attenuation factors from geometric spreading, sound directivity of source, air absorption, ground deflection and reflection, as well as effects from temperat......A model based on 2-D sound ray theory for aerodynamic noise propagation from wind turbine rotating blades is introduced. The model includes attenuation factors from geometric spreading, sound directivity of source, air absorption, ground deflection and reflection, as well as effects from...... temperature and airflow. At a given receiver point, the sound pressure is corrected by taking into account these propagation effects. As an overall assumption, the noise field generated by the wind turbine is simplified as a point source placed at the hub height of the wind turbine. This assumtion...... is reasonable, for the receiver is located in the far field, at distances from the wind turbine that are much longer than the diameter of the rotor....

Jet Noise Scaling in Dual Stream Nozzles

Science.gov (United States)

Khavaran, Abbas; Bridges, James

2010-01-01

Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.

Evaluating noise abatement measures using strategic noise maps

NARCIS (Netherlands)

Borst, H.C.; Miedema, H.M.E.; Laan, W.P.N. van der; Lohman, W.J.A.

2006-01-01

Noise annoyance due to transportation is widespread in industrialized countries and in urban areas in the developing countries. The European Noise Directive (END) requires an assessment of the noise situation as well as the formulation of action plans for the reduction of the number of people

Removing Noise From Pyrosequenced Amplicons

Directory of Open Access Journals (Sweden)

Davenport Russell J

2011-01-01

Full Text Available Abstract Background In many environmental genomics applications a homologous region of DNA from a diverse sample is first amplified by PCR and then sequenced. The next generation sequencing technology, 454 pyrosequencing, has allowed much larger read numbers from PCR amplicons than ever before. This has revolutionised the study of microbial diversity as it is now possible to sequence a substantial fraction of the 16S rRNA genes in a community. However, there is a growing realisation that because of the large read numbers and the lack of consensus sequences it is vital to distinguish noise from true sequence diversity in this data. Otherwise this leads to inflated estimates of the number of types or operational taxonomic units (OTUs present. Three sources of error are important: sequencing error, PCR single base substitutions and PCR chimeras. We present AmpliconNoise, a development of the PyroNoise algorithm that is capable of separately removing 454 sequencing errors and PCR single base errors. We also introduce a novel chimera removal program, Perseus, that exploits the sequence abundances associated with pyrosequencing data. We use data sets where samples of known diversity have been amplified and sequenced to quantify the effect of each of the sources of error on OTU inflation and to validate these algorithms. Results AmpliconNoise outperforms alternative algorithms substantially reducing per base error rates for both the GS FLX and latest Titanium protocol. All three sources of error lead to inflation of diversity estimates. In particular, chimera formation has a hitherto unrealised importance which varies according to amplification protocol. We show that AmpliconNoise allows accurate estimates of OTU number. Just as importantly AmpliconNoise generates the right OTUs even at low sequence differences. We demonstrate that Perseus has very high sensitivity, able to find 99% of chimeras, which is critical when these are present at high

Noise annoys: effects of noise on breeding great tits depend on personality but not on noise characteristics

NARCIS (Netherlands)

Naguib, M.; Van Oers, K.; Braakhuis, A.; Griffioen, M.; De Goede, P.; Waas, J.R.

2013-01-01

Anthropogenic noise can have serious implications for animals, especially when they communicate acoustically. Yet, the impacts of noise may depend not only on noise characteristics but also on an individual's coping style or personality. We tested whether noise is more disturbing if it masks

Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise.

Science.gov (United States)

Zhang, Mingji; Or, Siu Wing

2017-10-25

We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4-30.6 V/(T/m), a strong common-mode magnetic field noise rejection rate of gradient noise of 0.16-620 nT/m/ Hz in a broad frequency range of 1 Hz-170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/ f ) noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs.

Performance of Traffic Noise Barriers with Varying Cross-Section

Directory of Open Access Journals (Sweden)

Sanja Grubeša

2011-05-01

Full Text Available The efficiency of noise barriers largely depends on their geometry. In this paper, the performance of noise barriers was simulated using the numerical Boundary Element Method (BEM. Traffic noise was particularly considered with its standardized noise spectrum adapted to human hearing. The cross-section of the barriers was varied with the goal of finding the optimum shape in comparison to classical rectangular barriers. The barrier performance was calculated at different receiver points for a fixed barrier height and source position. The magnitude of the insertion loss parameter was used to evaluate the performance change, both in one-third octave bands and as the broadband mean insertion loss value. The proposed barriers of varying cross-section were also compared with a typical T-shape barrier of the same height.

ICBEN review of research on the biological effects of noise 2011-2014

Science.gov (United States)

Basner, Mathias; Brink, Mark; Bristow, Abigail; de Kluizenaar, Yvonne; Finegold, Lawrence; Hong, Jiyoung; Janssen, Sabine A; Klaeboe, Ronny; Leroux, Tony; Liebl, Andreas; Matsui, Toshihito; Schwela, Dieter; Sliwinska-Kowalska, Mariola; Sörqvist, Patrik

2015-01-01

The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health. PMID:25774609

Electromagnetic form factors at large momenta from lattice QCD

Science.gov (United States)

Chambers, A. J.; Dragos, J.; Horsley, R.; Nakamura, Y.; Perlt, H.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Somfleth, K.; Stüben, H.; Young, R. D.; Zanotti, J. M.; Qcdsf/Ukqcd/Cssm Collaborations

2017-12-01

Accessing hadronic form factors at large momentum transfers has traditionally presented a challenge for lattice QCD simulations. Here, we demonstrate how a novel implementation of the Feynman-Hellmann method can be employed to calculate hadronic form factors in lattice QCD at momenta much higher than previously accessible. Our simulations are performed on a single set of gauge configurations with three flavors of degenerate mass quarks corresponding to mπ≈470 MeV . We are able to determine the electromagnetic form factors of the pion and nucleon up to approximately 6 GeV2 , with results for the ratio of the electric and magnetic form factors of the proton at our simulated quark mass agreeing well with experimental results.

False-nearest-neighbors algorithm and noise-corrupted time series

International Nuclear Information System (INIS)

Rhodes, C.; Morari, M.

1997-01-01

The false-nearest-neighbors (FNN) algorithm was originally developed to determine the embedding dimension for autonomous time series. For noise-free computer-generated time series, the algorithm does a good job in predicting the embedding dimension. However, the problem of predicting the embedding dimension when the time-series data are corrupted by noise was not fully examined in the original studies of the FNN algorithm. Here it is shown that with large data sets, even small amounts of noise can lead to incorrect prediction of the embedding dimension. Surprisingly, as the length of the time series analyzed by FNN grows larger, the cause of incorrect prediction becomes more pronounced. An analysis of the effect of noise on the FNN algorithm and a solution for dealing with the effects of noise are given here. Some results on the theoretically correct choice of the FNN threshold are also presented. copyright 1997 The American Physical Society

The effects of observational correlated noises on multifractal detrended fluctuation analysis

Science.gov (United States)

Gulich, Damián; Zunino, Luciano

2012-08-01

We have numerically investigated the effects that observational correlated noises have on the generalized Hurst exponents, h(q), estimated by using the multifractal generalization of detrended fluctuation analysis (MF-DFA). More precisely, artificially generated stochastic binomial multifractals with increased amount of colored noises were analyzed via MF-DFA. It has been recently shown that for moderate additions of white noise, the generalized Hurst exponents are significantly underestimated for qeffects of additive noise, short- term memory and periodic trends, Physica A 390 (2011) 2480-2490]. In this paper, we have found that h(q) with q≥2 are also affected when correlated noises are considered. This is due to the fact that the spurious correlations influence the scaling behaviors associated to large fluctuations. The results obtained are significant for practical situations, where noises with different correlations are inherently present.

Emittance growth due to noise and its suppression with the Feedback system in large hadron colliders

International Nuclear Information System (INIS)

Lebedev, V.; Parkhomchuk, V.; Shiltsev, V.; Stupakov, G.

1993-03-01

The problem of emittance growth due to random fluctuation of the magnetic field in hadron colliders is considered. Based on a simple one-dimensional linear model, a formula for an emittance growth rate as a function of the noise spectrum is derived. Different sources of the noise are analyzed and their role is estimated for the Superconducting Super Collider (SSC). A theory of feedback suppression of the emittance growth is developed which predicts the residual growth of the emittance in the accelerator with a feedback system

Noise enhances information transfer in hierarchical networks.

Science.gov (United States)

Czaplicka, Agnieszka; Holyst, Janusz A; Sloot, Peter M A

2013-01-01

We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor.

Could driving safety be compromised by noise exposure at work and noise-induced hearing loss?

Science.gov (United States)

Picard, Michel; Girard, Serge André; Courteau, Marilène; Leroux, Tony; Larocque, Richard; Turcotte, Fernand; Lavoie, Michel; Simard, Marc

2008-10-01

A study was conducted to verify if there is an association between occupational noise exposure, noise-induced hearing loss and driving safety expanding on previous findings by Picard, et al. (2008) that the two factors did increase accident risk in the workplace. This study was made possible when driving records of all Quebec drivers were made available by the Societe de l'assurance automobile du Quebec (SAAQ is the state monopoly responsible for the provision of motor vehicle insurance and the compensation of victims of traffic accidents). These records were linked with personal records maintained by the Quebec National Institute of Public Health as part of its mission to prevent noise induced hearing loss in the workplace. Individualized information on occupational noise exposure and hearing sensitivity was available for 46,030 male workers employed in noisy industries who also held a valid driver's permit. The observation period is of five years duration, starting with the most recent audiometric examination. The associations between occupational noise exposure levels, hearing status, and personal driving record were examined by log-binomial regression on data adjusted for age and duration of exposure. Daily noise exposures and bilateral average hearing threshold levels at 3, 4, and 6 kHz were used as independent variables while the dependent variables were 1) the number of motor vehicle accidents experienced by participants during the study period and 2) participants' records of registered traffic violations of the highway safety code. The findings are reported as prevalence ratios (PRs) with their 95% confidence intervals (CIs). Attributable numbers of events were computed with the relevant PRs, lesser-noise, exposed workers and those with normal hearing levels making the group of reference. Adjusting for age confirmed that experienced workers had fewer traffic accidents. The data show that occupational noise exposure and hearing loss have the same effect on

Shot-noise Fano factor

Czech Academy of Sciences Publication Activity Database

Rajdl, K.; Lánský, Petr

2015-01-01

Roč. 92, č. 5 (2015), č. článku 052135. ISSN 2470-0045 Institutional support: RVO:67985823 Keywords : response functions * limit-theorems * spike trains * variability Subject RIV: BD - Theory of Information Impact factor: 2.252, year: 2015

The Effects of Syntactic Complexity on Processing Sentences in Noise

Science.gov (United States)

Carroll, Rebecca; Ruigendijk, Esther

2013-01-01

This paper discusses the influence of stationary (non-fluctuating) noise on processing and understanding of sentences, which vary in their syntactic complexity (with the factors canonicity, embedding, ambiguity). It presents data from two RT-studies with 44 participants testing processing of German sentences in silence and in noise. Results show a…

Noise abatement and traffic safety: The trade-off of quieter engines and pavements on vehicle detection.

Science.gov (United States)

Mendonça, C; Freitas, E; Ferreira, J P; Raimundo, I D; Santos, J A

2013-03-01

Road traffic sounds are a major source of noise pollution in urban areas. But recent developments such as low noise pavements and hybrid/electric engine vehicles cast an optimistic outlook over such an environmental problem. However, it can be argued that engine, tire, and road noise could be relevant sources of information to avoid road traffic conflicts and accidents. In this paper, we analyze the potential trade-offs of traffic-noise abatement approaches in an experimental study, focusing for the first time on the impact and interaction of relevant factors such as pavement type, vehicle type, listener's age, and background noise, on vehicle detection levels. Results reveal that vehicle and pavement type significantly affect vehicle detection. Age is a significant factor, as both younger and older people exhibit lower detection levels of incoming vehicles. Low noise pavements combined with all-electric and hybrid vehicles might pose a severe threat to the safety of vulnerable road users. All factors interact simultaneously, and vehicle detection is best predicted by the loudness signal-to-noise ratio. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spatio-temporal chaos and thermal noise in Josephson junction series arrays

International Nuclear Information System (INIS)

Dominguez, D.; Cerdeira, H.A.

1995-01-01

We study underdamped Josephson junction series arrays that are globally coupled through a resistive shunting load and driven by an rf bias current. We find that they can be an experimental realization of many phenomena currently studied in globally coupled logistic map. Depending on the bias current the array can show Shapiro steps but also spatio-temporal chaos or ''turbulence'' in the IV characteristics. In the turbulent phase there is a saturation of the broad band noise for a large number of junctions. This corresponds to a break down of the law of large numbers as seen in globally coupled maps. We study this phenomenon as a function of thermal noise. We find that when increasing the temperature the broad band noise decreases. (author). 8 refs, 1 fig

Highly noise resistant multiqubit quantum correlations

Science.gov (United States)

Laskowski, Wiesław; Vértesi, Tamás; Wieśniak, Marcin

2015-11-01

We analyze robustness of correlations of the N-qubit GHZ and Dicke states against white noise admixture. For sufficiently large N, the Dicke states (for any number of excitations) lead to more robust violation of local realism than the GHZ states (e.g. for N > 8 for the W state). We also identify states that are the most resistant to white noise. Surprisingly, it turns out that these states are the GHZ states augmented with fully product states. Based on our numerical analysis conducted up to N = 8, and an analytical formula derived for any N parties, we conjecture that the three-qubit GHZ state augmented with a product of (N - 3) pure qubits is the most robust against white noise admixture among any N-qubit state. As a by-product, we derive a single Bell inequality and show that it is violated by all pure entangled states of a given number of parties. This gives an alternative proof of Gisin’s theorem.

Highly noise resistant multiqubit quantum correlations

International Nuclear Information System (INIS)

Laskowski, Wiesław; Wieśniak, Marcin; Vértesi, Tamás

2015-01-01

We analyze robustness of correlations of the N-qubit GHZ and Dicke states against white noise admixture. For sufficiently large N, the Dicke states (for any number of excitations) lead to more robust violation of local realism than the GHZ states (e.g. for N > 8 for the W state). We also identify states that are the most resistant to white noise. Surprisingly, it turns out that these states are the GHZ states augmented with fully product states. Based on our numerical analysis conducted up to N = 8, and an analytical formula derived for any N parties, we conjecture that the three-qubit GHZ state augmented with a product of (N − 3) pure qubits is the most robust against white noise admixture among any N-qubit state. As a by-product, we derive a single Bell inequality and show that it is violated by all pure entangled states of a given number of parties. This gives an alternative proof of Gisin’s theorem. (paper)

The effects of noise reduction technologies on the acceptance of background noise.

Science.gov (United States)

Lowery, Kristy Jones; Plyler, Patrick N

2013-09-01

Directional microphones (D-Mics) and digital noise reduction (DNR) algorithms are used in hearing aids to reduce the negative effects of background noise on performance. Directional microphones attenuate sounds arriving from anywhere other than the front of the listener while DNR attenuates sounds with physical characteristics of noise. Although both noise reduction technologies are currently available in hearing aids, it is unclear if the use of these technologies in isolation or together affects acceptance of noise and/or preference for the end user when used in various types of background noise. The purpose of the research was to determine the effects of D-Mic, DNR, or the combination of D-Mic and DNR on acceptance of noise and preference when listening in various types of background noise. An experimental study in which subjects were exposed to a repeated measures design was utilized. Thirty adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Acceptable noise levels (ANLs) were obtained using no noise reduction technologies, D-Mic only, DNR only, and the combination of the two technologies (Combo) for three different background noises (single-talker speech, speech-shaped noise, and multitalker babble) for each listener. In addition, preference rankings of the noise reduction technologies were obtained within each background noise (1 = best, 3 = worst). ANL values were significantly better for each noise reduction technology than baseline; and benefit increased significantly from DNR to D-Mic to Combo. Listeners with higher (worse) baseline ANLs received more benefit from noise reduction technologies than listeners with lower (better) baseline ANLs. Neither ANL values nor ANL benefit values were significantly affected by background noise type; however, ANL benefit with D-Mic and Combo was similar when speech-like noise was present while ANL benefit was greatest for Combo when speech spectrum noise was

Community noise

Science.gov (United States)

Bragdon, C. R.

Airport and community land use planning as they relate to airport noise reduction are discussed. Legislation, community relations, and the physiological effect of airport noise are considered. Noise at the Logan, Los Angeles, and Minneapolis/St. Paul airports is discussed.

A Recording-Based Method for Auralization of Rotorcraft Flyover Noise

Science.gov (United States)

Pera, Nicholas M.; Rizzi, Stephen A.; Krishnamurthy, Siddhartha; Fuller, Christopher R.; Christian, Andrew

2018-01-01

Rotorcraft noise is an active field of study as the sound produced by these vehicles is often found to be annoying. A means to auralize rotorcraft flyover noise is sought to help understand the factors leading to annoyance. Previous work by the authors focused on auralization of rotorcraft fly-in noise, in which a simplification was made that enabled the source noise synthesis to be based on a single emission angle. Here, the goal is to auralize a complete flyover event, so the source noise synthesis must be capable of traversing a range of emission angles. The synthesis uses a source noise definition process that yields periodic and aperiodic (modulation) components at a set of discrete emission angles. In this work, only the periodic components are used for the source noise synthesis for the flyover; the inclusion of modulation components is the subject of ongoing research. Propagation of the synthesized source noise to a ground observer is performed using the NASA Auralization Framework. The method is demonstrated using ground recordings from a flight test of the AS350 helicopter for the source noise definition.