Many underwater bioacoustical recording experiments (e.g., fish sound production during courtship or agonistic encounters) are usually conducted in a controlled laboratory environment of small-sized tanks. The effects reverberation, resonance, and tank size on the characteristics recorded inside small tanks have never been fully addressed, although these factors known to influence recordings. In this work, 5-cycle tone bursts 1-kHz were used as test signal investigate 170-l rectangular glass...

The double network concept, based on the fracture of sacrificial bonds, has been revolutionary toward creation robust soft materials. Based essence hydrogels, macroscale, three-dimensional printed rigid networks are embedded within silicone rubber stretchable matrices. Preferential results in a ∼60 time increase stiffness and ∼50% work extension compared with neat matrix. Maximizing yield strength while maintaining multistep internal occurs when approaches Upon determining optimal strength,...

Abstract We propose a new concept that utilizes the difference in Poisson's ratio between component materials as strengthening mechanism increases effectiveness of sacrificial bond toughening macroscale double-network (Macro-DN) materials. These Macro-DN composites consist macroscopic skeleton imbedded within soft elastic matrix. varied reinforcing by introducing auxetic or honeycomb functional structures results Poisson’s mismatch and During uniaxial tensile experiments, high strength...

(2002). ANALYSES OF SMALL TANK ACOUSTICS: EMPIRICAL AND THEORETICAL APPROACHES. Bioacoustics: Vol. 12, No. 2-3, pp. 330-332.

Abstract The boundary-element method (BEM) is applied to calculate target strength (TS) and extinction cross-section of a scatterer. scattering amplitudes four types prolate spheroid, namely, the vacant, rigid, liquid-filled, gas-filled, are calculated using BEM. Comparison between results BEM prolate-spheroid model (PSM), which numerical calculation spheroidal-wave functions, shows excellent agreement for liquid-filled spheroids. TS gas-filled by BEM, resonance at low frequency. lowest...

To estimate the acoustic back scattering cross section of a fish, numerical approach is newly developing. This method comprises three dimensional morphometry fish body structure by X-ray computed tomography (X-ray CT) and calculation boundary element (BEM). The basic idea this simple: incorporating three-dimensional shape information obtained CT scan into BEM. data processability method, which from taking to generating input for calculation, tested on sample Horse Mackerel (Trachurus japonicus).

Forward and bistatic scattering of sound by individual fish at frequencies 120 200 kHz have recently been measured in the laboratory following an earlier experiment conducted acoustic frequency 38 Ding [J. Acoust. Soc. Am. 101, 3398–3404 (1997)]. The results forward-scattering strength obtained here, combined with those Ding, provide empirical dependence on frequency. It is observed that increases rapidly much stronger than backscattering strength. Scattering patterns, or as a function...

A pseudospark switch, which can substitute thyratrons in pulsed power applications, was successfully tested at hold-off voltages up to 25 kV and peak currents 18 kA. lifetime test performed until 3.6×10 7 shots, without showing any significant degradation of the switch. Current rise rates 6×10 11 A/s a current reversal capability 100% are additional features this help improve performance devices.

The machine diagnosis based on vibration measurement and analysis faces the new practical phase of signal method that is superior to aural objectivity by good use advanced technology. defective gear existed in rotating as a target can be identified feature quantity each factor overall judgment should needed. In this paper determination for best sensor position purposed relation between characteristic various gears extracted grasped. Also it concluded dynamic device taken into account.

The Boundary Element Method (BEM) is applied to calculate the target strength (TS) and total cross section of a scatterer. scattering amplitudes prolate spheroids four types, namely, vacant, rigid, liquid-filled, gas-filled are calculated by BEM. comparison results BEM those Prolate Spheroid Model (PSM), which numerical calculation using spheroidal wave functions, shows excellent agreement for liquid-filled spheroids. TS spheroid resonance at low frequency.

Noise is one of the important problems for hydroacoustic surveys fisheries resources, because it may cause a large error in estimated results and shorten detectable range. It necessary to estimate reduce contribution acoustic noise precise accurate surveys. classified into low-frequency (audible by fish) high-frequency (affecting echo sounders). High-frequency usually an overestimate return. The average power was measured echo-integrator. echo-integrator output converted equivalent spectrum...

The penetration of gamma-rays through a metal pipe was measured. inner diameter the lead used in this experiment 5.0 cm and those iron tubes were 9.6 cm. 137Cs 60Co point gamma-ray sources placed on axis tube. which passed tube scattered from wall detected by 3 in. long Nal (TI) scintillator. Energy spectra measured at several source positions, energy number build-up factors obtained spectra.

The double network concept has been revolutionary in its ability to turn soft, brittle hydrogels into tough, robust materials with mechanical properties that match the best synthetic elastomers. Double consist of two interpenetrating networks, where each a specific response: “first network” acts as sacrificial network, consisting rigid, extended relatively low loading percentage, and “second is globally percolated, stretchable network. When hydrogel stretched, covalent bonds first break,...

A squid has been specified as a kind of fish that to managed scientifically. Estimation its resources via acoustic surveys is required. But the basic data target strength (TS) are limited. So far, in measurements TS pattern fish, echo levels observed while changing aspect fish. On other hand, since more fragile than and unstable shape, rotating unit not available for squid. positioning system makes transducer scan precisely around an aquatic suspended water designed. This loaded electric...