The Open Acoustics Journal
About: The Open Acoustics Journal is an academic journal. The journal publishes majorly in the area(s): Soundproofing & Noise. Over the lifetime, 34 publication(s) have been published receiving 245 citation(s).
Abstract: This paper explores the use of acoustics for the recovery of oil in oil-water emulsions. A series of experimental studies were conducted using acoustic standing waves in resonant cavities as means of trapping oil droplets and enhancing oil separation. Several cavity configurations were explored and the frequency range used was between 1 MHz-2 MHz. Oil-water emulsions studied were made using mineral oil and motor oil.
Abstract: The problem of vibrations of fluid-conveying pipes resting on a two-parameter foundation model such as the Pasternak-Winkler model is studied in this paper. Fluid-conveying pipes with ends that are pinned-pinned, clamped- pinned and clamped-clamped are considered for study. The frequency expression is derived using Fourier series for the pinned-pinned case. Galerkin's technique is used in obtaining the frequency expressions for the clamped-pinned and clamped-clamped boundary conditions. The effects of the transverse and shear parameters related to the Pasternak- Winkler model and the fluid flow velocity parameter on the frequencies of vibration are studied based on the numerical results obtained for various pipe end conditions. From the results obtained, it is observed that the instability caused by the fluid flow velocity is effectively countered by the foundation and the fluid conveying pipe is stabilized by an appropriate choice of the stiffness parameters of the Pasternak-Winkler foundation. A detailed study is made on the influence of Pasternak-Winkler foundation on the frequencies of vibration of fluid conveying pipes and interesting conclusions are drawn from the numerical results presented for pipes with different boundary conditions.
Abstract: In this paper, ultrasonic properties like ultrasonic attenuation, sound velocities, acoustic coupling constants and thermal relaxation time have been studied in hexagonal structured metals Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er) and Thulium (Tm) along unique axis at room temperature For the evaluations of ultrasonic properties, secondand thirdorder elastic constants have been computed also The peculiar behavior of these metals is found at 55° due their least thermal relaxation time and highest Debye average velocity Dy is more ductile, stable, perfect metal in comparison to other chosen metals due to its lowest value of attenuation So we predict that Dy is most suitable lanthanide metals for material science and engineering
Abstract: This paper describes combined experiments and simulations to automate the extraction of ultrasonic guided wave mode arrivals in order to gain quantitative information about large-diameter pipeline coatings. The dynamic wavelet fingerprint technique (DWFT) is used to show differences between unknown coatings as well as to identify the presence of delamination and grinding flaws within the Lamb wave propagation path. Combined with complex multi-layered models to help interpret the guided wave feature changes, this extraction algorithm can be used for the detection of hidden flaws under a variety of protective coatings without having to disturb the coating or pipeline flow. High-resolution supercomputer simulations are developed using the elastodynamic finite integration technique (EFIT) accounting for the 3D interaction of realistic Lamb wave beams with finite-sized coating delaminations.
Abstract: The incidence of collisions between motorcyclists and other vehicles may be significantly reduced by research that improves the acoustic awareness of cyclists, and thus heightens the ability of cyclists to respond to unexpected incursions from the surrounding traffic. We use our hearing as an early warning system, and hearing swiftly redirects our vision and attention. This shift in gaze is critical to our capacity to assess the location, direction of travel, and velocity of approaching vehicles. The present study was composed of two experiments. In the first experiment a Neumann KU-100 dummy head with embedded binaural microphones was used to measure noise levels in a motorcycle helmet as a function of velocity. Noise levels were measured in two helmets, one with active noise reduction technology, and one without. The results showed that noise levels exceeded 100 dB (A) at highway speeds in the absence of noise reduction technology. The helmet with active noise control ear muffs was able to attenuate helmet noise by up to 26 dB. Active noise control technology shows great promise for noise reduction for the motorcycle helmet industry, and the development of "quiet" helmets is important for both hearing conservation and highway safety. The second experiment surveyed subjective perceptions of helmet noise by motorcyclists. The results from the present sample showed that 92.1% of the respondents objected to the high noise levels associated with cycling, 63.5 % wore earplugs, 46.8% reported tinnitus, and 95.2% wanted a quieter helmet.
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