Volume 109, Issue 3, March 2001
Index of content:
- NOISE: ITS EFFECTS AND CONTROL 
109(2001); http://dx.doi.org/10.1121/1.1345698View Description Hide Description
Two numerical models are presented for the prediction of sound leakage through openings in thin hard barriers. The first numerical method is based on a simple procedure of numerical integration that can be implemented straightforwardly. This model is a more general approach, suitable for barriers with arbitrary gaps. The second model is a new method that permits prediction of sound leakage due to the presence of horizontal gaps in a long barrier. In the new method, effective barriers of appropriate heights represent the edges of the horizontal gaps. The sounddiffracted by each effective barrier is calculated by a closed-form analytic expression. The total sound-pressure level is determined from a sum of these diffracted fields. Hence, the new method is fast, simple, and intuitive, allowing the leakage to be assessed accurately. The validity of these two numerical models is confirmed by precise experimental measurements.
109(2001); http://dx.doi.org/10.1121/1.1340642View Description Hide Description
Although accumulating evidence over the past two decades points towards noise as an ambient stressor for children, all of the data emanate from studies in high-intensity, noise impact zones around airports or major roads. Extremely little is known about the nonauditory consequences of typical, day-to-day noise exposure among young children. The present study examined multimethodological indices of stress among children living under 50 dB or above 60 dB (A-weighted, day-night average sound levels) in small towns and villages in Austria. The major noise sources were local road and rail traffic. The two samples were comparable in parental education, housing characteristics, family size, marital status, and body mass index, and index of body fat. All of the children were prescreened for normal hearingacuity. Children in the noisier areas had elevated resting systolic blood pressure and 8-h, overnight urinary cortisol. The children from noisier neighborhoods also evidenced elevated heart rate reactivity to a discrete stressor (reading test) in the laboratory and rated themselves higher in perceived stress symptoms on a standardized index. Furthermore girls, but not boys, evidenced diminished motivation in a standardized behavioral protocol. All data except for the overnight urinary neuroendocrine indices were collected in the laboratory. The results are discussed in the context of prior airport noise and nonauditory health studies. More behavioral and health research is needed on children with typical, day-to-day noise exposure.