The role of annoyance in the relation between transportation noise and children's health and cognition

On the basis of this study it cannot be ruled out that the appraisal of the noise affects the association between air and road traffic noise exposure and children's health and cognition. However, the conclusion is limited due to the relatively small group of annoyed children, which may have influenced our group comparisons. Furthermore, the observed relation between annoyance and perceived health is possibly biased due to the fact that both were measured within the same questionnaire. These are the main conclusions of a cross-sectional multi-center study carried out among 2,844 schoolchildren (age 9-11 years) attending 89 primary schools around three European airports. The aim was to investigate how annoyance affects the relation between air and road traffic noise exposure and children's health and cognition. Different, sometimes competing, working mechanisms of how noise affects children's health are suggested. Some effects are supposed to be precipitated through (chronic) stress, while others may arise directly. There is still no theory that can adequately account for the circumstances in which noise will affect cognitive performance.     

The sensitivity of photoemulsions and its relation to the sensitivity of a photocathode

The sensitivity limitations arising from fluctuations in photoemulsions are discussed and the conditions under which the limitations reach a minimum are described. The photoemulsion area which corresponds to a minimum number of quanta at a certain registration accuracy is derived. Estimates are given which indicate how the required light sum increases when the area exceeds the optimum value. The sensitivities of photoemulsions and photocathodes are compared. It could be shown that the photoemulsion sensitivity deteriorates to a certain extent when the exposure range increases. A selection of the exposure working region is suggested which, in contrast to the linear portion of the characteristic curve, permits measuments with a smaller light input and in a wider exposure range.     

Application of MetaRail railway noise measurement methodology: comparison of three track systems

Within the fourth RTD Framework Programme, the European Union has supported a research project dealing with the improvement of railway noise (emission) measurement methodologies. This project was called MetaRail and proposed a number of procedures and methods to decrease systematic measurement errors and to increase reproducibility. In 1999 the Austrian Federal Railways installed 1000 m of test track to explore the long-term behaviour of three different ballast track systems. This test included track stability, rail forces and ballast forces, as well as vibration transmission and noise emission. The noise study was carried out using the experience and methods developed within MetaRail. This includes rail roughness measurements as well as measurements of vertical railhead, sleeper and ballast vibration in parallel with the noise emission measurement with a single microphone at a distance of 7.5 m from the track. Using a test train with block- and disc-braked vehicles helped to control operational conditions and indicated the influence of different wheel roughness.It has been shown that the parallel recording of several vibration signals together with the noise signal makes it possible to evaluate the contributions of car body, sleeper, track and wheel sources to the overall noise emission. It must be stressed that this method is not focused as is a microphone-array. However, this methodology is far easier to apply and thus cheaper. Within this study, noise emission was allocated to the different elements to answer questions such as whether the sleeper eigenfrequency is transmitted into the rail.     

A survey of community attitudes towards noise near a general aviation airport

This paper describes a community attitudinal noise survey performed in the vicinity of the Decatur, Illinois Airport. Two hundred thirty-one respondents were drawn from four distinct noise zones in populated areas near the airport. The day/night average sound levels (DNL) ranged from 44-66 dB. The area is otherwise quiet, residential with large (1/2 acre) lots. The primary analysis arrayed the percent of respondents highly annoyed versus DNL. Good agreement was found between the results of this survey and the general relation developed by Schultz from surveys worldwide, primarily in the vicinity of large commercial airports and highways. In addition, reasonable comparisons were found between respondent estimates of the number of aircraft operations and actual traffic counts. It was also found that respondents who were highly annoyed by aircraft noise were three to four times as likely to be highly annoyed by some other noise than were other respondents.     

The role of injunctions in noise nuisance

The circumstances in which a person with a legal interest in land may be granted a perpetual injunction to restrain a noise nuisance are critically examined. A householder's legal rights should not be overridden by the interests of club members or of the public in attending motor boat racing events organised by such a club, so as to deprive him of the remedy of injunction. The Court of Appeal so held in the recent decision of Kennaway v. Thompson 30 April, 1980.The principles which the court applies in considering the granting of an interlocutory injunction to a local authority to restrain a noise which is a nuisance under the Control of Pollution Act, Section 58 (8), are also considered.     

1/f noise in metal films: The role of the substrate

We have examined the temperature dependence of voltage (“1/f”) noise in Cu and Ag films on quartz and sapphire substrates. Our data suggest that two types of voltage noise occur simultaneously in metal films. One type of noise depends on the substrate and is weakly temperature-dependent; the remaining noise is strongly temperature-dependent and independent of the substrate.     

Limits to the sensitivity of a low noise compact atomic gravimeter

A detailed analysis of the most relevant sources of phase noise in an atomic interferometer is carried out, both theoretically and experimentally. Even a short interrogation time of 100 ms allows our cold atom gravimeter to reach an excellent short term sensitivity to acceleration of 1.4×10^-8g at 1 s. This result relies on the combination of a low phase noise laser system, efficient detection scheme and good shielding from vibrations. In particular, we describe a simple and robust technique of vibration compensation, which is based on correcting the interferometer signal by using the ac acceleration signal measured by a low noise seismometer. PACS  32.80.Pj; 42.50.Vk; 39.20.+q     

Surf-generated noise signatures: a comparison of plunging and spilling breakers

Range-time-frequency distributions of surf-generated noise were measured within the surf zone during the SandyDuck'97 experiment at Duck, NC. A 24-phone, 138-m, bottom-mounted, linear array located along a line perpendicular to the shore at a depth of 1 to 3 m recorded the surf-generated noise. Concurrent video measurements of the location, size, and time-evolution of the individual breaking waves directly above the array were made from a nearby 43-m tower. Source level spectra are obtained by using a modified fast field program to account for water column and geoacoustic propagation from the distributed source region to an individual hydrophone. The length, location, and orientation of the leading edge of breakers are tracked in time from rectified video images. It is observed that the source levels from spilling breakers are lower (approximately 5-10 dB) than those produced by plunging breakers that occurred during the same time period. Plunging breakers generated time-frequency signatures with a sharp onset while spilling breakers' signatures had a gradual low-frequency precursor. Range-time signatures of plunging breakers indicate a burst of acoustic energy while spilling breakers' signatures depict sound being generated over a longer time period with the source region moving with the breaking surface wave.     

The role of the envelope in processing iterated rippled noise.

Iterated rippled noise (IRN) is generated by a cascade of delay and add (the gain after the delay is 1.0) or delay and subtract (the gain is -1.0) operations. The delay and add/subtract operations impart a spectral ripple and a temporal regularity to the noise. The waveform fine structure is different in these two conditions, but the envelope can be extremely similar. Four experiments were used to determine conditions in which the processing of IRN stimuli might be mediated by the waveform fine structure or by the envelope. In experiments 1 and 3 listeners discriminated among three stimuli in a single-interval task: IRN stimuli generated with the delay and add operations (g = 1.0), IRN stimuli generated using the delay and subtract operations (g = -1.0), and a flat-spectrum noise stimulus. In experiment 2 the listeners were presented two IRN stimuli that differed in delay (4 vs 6 ms) and a flat-spectrum noise stimulus that was not an IRN stimulus. In experiments 1 and 2 both the envelope and waveform fine structure contained the spectral ripple and temporal regularity. In experiment 3 only the envelope had this spectral and temporal structure. In all experiments discrimination was determined as a function of high-pass filtering the stimuli, and listeners could discriminate between the two IRN stimuli up to frequency regions as high as 4000-6000 Hz. Listeners could discriminate the IRN stimuli from the flat-spectrum noise stimulus at even higher frequencies (as high as 8000 Hz), but these discriminations did not appear to depend on the pitch of the IRN stimuli. A control experiment (fourth experiment) suggests that IRN discriminations in high-frequency regions are probably not due entirely to low-frequency nonlinear distortion products. The results of the paper imply that pitch processing of IRN stimuli is based on the waveform fine structure.     

Aircraft noise annoyance modeling: Consideration of noise sensitivity and of different annoying acoustical characteristics

Noise annoyance due to aircraft flyover noise was assessed under laboratory conditions. The main objectives of the study were: (i) to identify influential acoustical features of noise annoyance, (ii) to propose noise indices to characterize these acoustical features and (iii) to enhance annoyance models including influential acoustical and non-acoustical variables. Therefore, a verbalization task was performed by the participants of the experiment to collect their whole impression concerning the aircraft flyover noises for which they rated annoyance. This verbalization task highlights that noise annoyance was influenced by three main acoustical features: (i) the spectral content, (ii) the temporal variation and (iii) the perceived sound intensity. Four combinations of noise indices were used to propose multilevel annoyance models, in combination with the individual noise sensitivity. Noise sensitivity was found to highly contribute to annoyance models and should therefore be considered in future studies dealing with noise annoyance due to aircraft noise. Different combinations of noise indices coupled with noise sensitivity were found to be promising for future studies that aim to enhance current annoyance models.     

A sensitivity comparison of three photoacoustic cells containing a single microphone,a differential dual microphone or a cantilever pressure sensor

Three photoacoustic (PA) cells designed for trace-gas sensing were compared by measuring absorption by the P(15) rotational line of the vibrational combination band of acetylene using a distributed-feedback diode laser. Normalised sensitivities were determined for each cell by analysis of the signal to noise ratios of acquired spectra. The first cell was constructed in-house, and contained a single electret microphone held in a stainless steel tube. The second cell was a differential PA cell that contained two microphones housed in identical flow tubes, with one microphone to detect the PA signal and the other to determine background noise levels. The third cell contained a novel cantilever pressure sensor, movement of which was measured by a compact laser interferometer. Normalised sensitivities (2σ) of 3.1×10^-7, 1.7×10^-7 and 2.2×10^-9 cm^-1 W Hz^-1/2, respectively, were obtained. An erbium-doped fibre amplifier was used to amplify the laser power, and a detection limit of 9.8×10¹⁰ molecule cm^-3 was obtained using the cantilever pressure sensor PA cell, with a laser power of 1.17 W. This detection limit corresponded to a mixing ratio of 14.5 parts per billion by volume at 277 mbar. PACS 82.80.Kq; 42.62.Fi; 82.80.Gk     

Individual differences in sensitivity to traffic noise: An empirical study

Repeated interview surveys were made in surburban residential areas of London and Liverpool. In both cities two sites were selected according to the noise exposure level (70 or 80 dB(A) 18 hour L₁₀, 1 metre from dwelling facade). The characteristics of the neighbourhoods were similar in all other relevant respects. The initial sample size obtained was 413 which was reduced by 21% when the interviews were repeated. Questions included noise dissatisfaction semantic differential scales, sensitivity to noise scales, environmental sensitivity scales, and classificatory questions. Two smaller random samples of 25 respondents selected from each of the noisy sites were also given two personality tests. It was found that (a) there was no evidence to suggest that the noise annoyance distributions were not normal—more specifically, they did not appear to be bimodal; (b) retest correlation coefficients were low but significant, indicating acceptable reliability of the noise dissatisfaction scale; (c) the reliability of the self-rating noise sensitivity scale was also found to be low but significant; (d) no personality factor was found to relate to annoyance or sensitivity to noise in a consistent manner. A general conclusion drawn was that noise dissatisfaction variation is due more to randomness in response to the measuring instrument than to individual differences in sensitivity to noise.     

A theoretical comparison of three fringe analysis methods for determining the three-dimensional shape of an object in the presence of noise

Various levels of random noise have been added to simulated digital images of a spherical dome illuminated by fringes projected from an offset angle. The noisy images have then been analysed using Fourier transform profilometry, phase shifting profilometry and spatial phase detection. The theoretical dome was subtracted from the domes reconstructed using these methods to form error maps. The maximum and RMS errors for each error map were calculated and plotted against the added noise level. At low levels of added noise the phase shifting method produced the lower errors, but above around 10% noise the Fourier transform method was better. Only at very high levels of added noise did the spatial phase detection method achieve the lowest errors.     

The role of nine-quark-state in three nucleon systems

The nine-quark-state role in three nucleon systems is discussed. The hybrid model for the³He wave function which takes into account only the three-nucleon and the ninequark components is used to describe the³He magnetic form factor. The probability of the nine-quark-state in³He is estimated to be 20%.     

Stability of convective patterns in reaction fronts: a comparison of three models

Autocatalytic reaction fronts generate density gradients that may lead to convection. Fronts propagating in vertical tubes can be flat, axisymmetric, or nonaxisymmetric, depending on the diameter of the tube. In this paper, we study the transitions to convection as well as the stability of different types of fronts. We analyze the stability of the convective reaction fronts using three different models for front propagation. We use a model based on a reaction-diffusion-advection equation coupled to the Navier-Stokes equations to account for fluid flow. A second model replaces the reaction-diffusion equation with a thin front approximation where the front speed depends on the front curvature. We also introduce a new low-dimensional model based on a finite mode truncation. This model allows a complete analysis of all stable and unstable fronts.     

Overview: The constructive role of noise in fluctuation driven transport and stochastic resonance

Random noise is typically thought of as the enemy of order rather than as a constructive influence. Recent work has shown however that under certain circumstances, noise and Brownian motion can facilitate transmission of information via a mechanism know as stochastic resonance, and help systems use chemical energy and nonequilibrium fluctuations to drive directed motion via fluctuation driven transport. In this focus issue we have collected several articles that capture the flavor of these developing fields and point the way to new directions for research. (c) 1998 American Institute of Physics.