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Egglestonichthys fulmen sp. nov. (Teleostei: Gobiidae) is described on the basis of a single specimen (21.7 mm in standard length) collected from 250 m depth off Okinawa Island, Ryukyu Islands, Japan. The new species is characterized by the following combination of characters: anal-fin rays I, 9; pectoral-fin rays 17, lower rays not free from membrane; longitudinal scale series 25; transverse scales 8; pre-dorsalfin scale rows 8; cheek and opercle naked; pelvic frenum absent; caudal fin lanceolate, its length 32.2% of SL; interorbital width very narrow, 1.2% of HL (much narrower than pupil diameter); no spicules or odontoid processes on outer surface of gill arches; and body whitish, upper half with broken zigzag pattern of bright yellow patches and associated scattered black melanophores in fresh specimens (melanophores retained in preserved specimens). Several characters, including pectoral-fin ray count, interorbital width, and coloration uniquely distinguish the new species from congeners. [ABSTRACT FROM AUTHOR]

The Lepadichthys lineatus complex (Gobiesocidae: Diademichthyinae) is defined by three unique characters within Lepadichthys: (a) upper‐jaw lip fused with snout skin, usually lacking a distinct groove between the dorsal lip margin and snout (if present, very weak, restricted to posterior portion of jaw); (b) snout tip well extended, distinctly beyond lower‐jaw tip; and (c) inner surface of both lips with oral papillae. A taxonomic review of the complex recognized four valid species: Lepadichthys geminus sp. nov. (southern Japan and Indonesia), Lepadichthys heemstraorum sp. nov. (southwestern Indian Ocean), Lepadichthys polyastrous sp. nov. (southwestern Indian Ocean) and L. lineatus Briggs, 1966 (Red Sea, Arabian Sea, Seychelles and Sri Lanka). L. geminus and L. lineatus are distinct from L. heemstraorum and L. polyastrous in having a circular (vs. elliptical) disc and more posteriorly located anus [L. geminus and L. lineatus with disc length and width 15.0–18.7 (mean 16.9) and 12.9–16.5 (14.6) % LS, respectively, and length to width ratio 1.03–1.25 cf. L. heemstraorum and L. polyastrous, 17.0–21.5 (18.9) and 11.6–15.2 (13.0) % LS, respectively, and 1.26–1.61; pre‐anus length and disc to anus length 65.1–73.6 (68.7) and 25.7–31.6 (28.6) % LS, respectively vs. 60.2–68.3 (65.3) and 21.6–28.9 (25.5) % LS, respectively]. Body depth (as % of LS) is also useful to distinguish L. geminus and L. polyastrous from L. heemstraorum and L. lineatus [viz., 12.7–16.1 (14.4) in L. geminus and 10.8–14.9 (13.1) in L. polyastrous vs. 15.0–17.1 (15.9) in L. heemstraorum and 14.6–18.9 (16.8) in L. lineatus]. L. geminus differs distinctly from other species in the complex as follows: snout tip directed upward, usually on same horizontal level with lower margin of eye lens (lateral view) (vs. directed somewhat downward, horizontal level usually between lower margins of eye and eye lens in L. heemstraorum and L. lineatus, lower margin of eye in L. polyastrous); and lower abdomen with two yellow stripes (vs. a single stripe along ventral midline in L. polyastrous and L. lineatus, unknown in L. heemstraorum). L. polyastrous has unique patterns of yellow dots on the dorsal and ventral body surfaces, forming c. six to eight and three to five longitudinal rows, respectively [vs. usually forming c. three to five longitudinal rows and a single broken line, respectively, in L. geminus and L. lineatus; yellow dots usually absent in L. heemstraorum]. A poorly known species, Lepadichthys caritus Briggs, 1969, is regarded as a junior synonym of L. lineatus. [ABSTRACT FROM AUTHOR]

In the present report, the noise-shielding efficiency of balconies with ceiling-mounted reflectors on the façades of high-rise buildings is examined through full-scale field measurements. The reflectors are designed to reflect direct and diffracted waves incident on the balcony ceiling outside the balcony. Field measurements are conducted to investigate the performance of the reflectors on intermediate floors of a high-rise dwelling adjacent to a railway. The reflectors reduce railway noise by approximately 5 dB, in A-weighted sound pressure level, compared to an ordinary balcony. The noise-shielding efficiency of a balcony equipped with reflectors is greater than that of an absorbing balcony. [ABSTRACT FROM AUTHOR]

The performance of balconies with ceiling-mounted reflectors on a high-rise building façade is examined using numerical analyses and scale-model experiments. The reflectors are designed to reflect direct and diffracted waves incident on the ceiling outside the balcony. The sound pressure reduction, provided by the reflectors, on a window surface adjacent to the balcony is evaluated at intermediate floors levels. In terms of A-weighted sound pressure levels, a balcony equipped with reflectors reduces road traffic noise by 7-10 dB(A), compared to an ordinary balcony, at incident angles of noise close to the angle for which the reflectors are designed. The efficiency is roughly the same as, or greater than, that of a balcony with an absorbent ceiling. However, it is also shown that when the vertical incident angle of the noise is smaller than the design angle of the reflectors, or the horizontal incident angle is large, efficiency is reduced. [ABSTRACT FROM AUTHOR]

The boundary element method (BEM) is widely used for sound field analysis problems; however, it has a non-uniqueness problem in the exterior domain. Various methods to avoid this problem have been developed; however, these are not easily applied to the BEM. In this paper, a simple method called the “ICA-Ring (inner cavity ringing) method” is proposed for avoiding the non-uniqueness problem, and this method is applied to the BEM in both single and plural domains. The concept of the ICA-Ring method is that a scatterer in free space is hollowed as a shell and the volume is smaller; the eigenfrequencies are shifted to a higher range. Next, the mechanism of the non-uniqueness problem in plural domains and a reason of the application of the ICA-Ring method to the case of plural domains are explained. Finally, some results calculated by the BEM using the ICA-Ring method are shown. The calculational condition is that a cylinder with radius 0.125 m floats in two-dimensional free space. In this case, no calculational errors exist in 1–6000 Hz in both single and plural domains, when the thickness of the shell is 20 mm. The ICA-Ring method does not need to modify an existing computer program of conventional BEM. [ABSTRACT FROM AUTHOR]

An improved hybrid method is proposed for analyzing sound scattering by a periodic structure. Part of the scattered field formulated with the mode expansion method is combined with other components of the field formulated with the boundary integration method in one period of the structure. Structures treated by this method can have arbitrary periodic forms made of locally reactive boundaries and porous materials. The oblique incident absorption coefficient of the structure is obtained simply from the reflection factor calculated for each elemental wave of the scattered field. The accuracy of the method is demonstrated by the agreement between calculated and measured values of the normal absorption coefficient of some test structures. [Copyright &y& Elsevier]

This paper examines the sound shielding efficiency of a noise barrier having an acoustically soft cylindrical edge, as it compares to that provided by the well-known absorptive cylindrical edge. It has been reported that the waterwheel-shaped cylinder (acoustic tubes in a radial arrangement) approximates a soft surface cylinder, and that the sound shielding efficiency of a noise barrier is improved by placing the cylinder on its edge. The efficiency of the waterwheel-shaped edge barrier is strongly frequency dependent, thus the improvement in overall sound pressure level is smaller than expected when the source is broadband noise. The present study investigates the use of varied tube depths to improve the efficiency of the waterwheel-shaped edge. It is shown that adding tubes of different depths can flatten the frequency dependence, and that such tubes are only needed in the upper half of the cylinder. These findings led to the design of a new edge device for controlling road traffic noise, whose numerical simulations suggest that it is twice as effective in overall sound pressure level as the original waterwheel with uniform-depth channels. © 1999 Acoustical Society of America. [ABSTRACT FROM AUTHOR]

This study presents a new way of estimating the sound field in a room with walls that do not reflect the incident sound specularly. So far the reflection characteristics of these walls have been considered to be perfectly diffuse or a mixture of partially diffuse and partially specular. The aim of this study is to introduce the real reflection characteristics of the walls into the simulation procedure for the sound field. The estimation procedure is essentially based on the Monte Carlo simulation method. For simplicity, the uneven walls are assumed to be periodically corrugated. Prior to the simulation, the reflection characteristics of the periodically corrugated wall are analyzed by wave theoretical methods, and the result, which contains the directions and magnitudes of the reflected waves, is used in the simulation procedure. The energy impulse responses estimated by the method presented are compared with those obtained by the ordinary method based only on geometrical theory. [ABSTRACT FROM AUTHOR]