helpiraq9034

In this paper, the sound transmission loss (STL) of multi-layered infinite micro-perforated plates (MPPs) is studied. A prediction model for the STL of the multi-layered infinite MPPs is developed, where each MPP may or may not have a perforation, and the number of MPPs is arbitrary. When the frequency of interest is well below the critical frequency of the plate such that the effect of flexural vibration can be neglected compared to that of the inertia term, the mass is replaced by an equivalent complex mass. For numerical examples, single-, double- and triple-layered MPPs are studied. As the perforation ratio increases, the magnitude of the equivalent complex mass decreases rapidly, which in turn results in a decrease of the STL. It is observed that for very small perforation ratios, the mass-spring resonance frequencies in double- and triple-layered MPPs move toward a higher frequency as the perforation ratios increase. In addition, the dips at the resonance frequencies become blunt with increases in the perforation ratios due to the artificial damping induced by micro-perforations. It is also found that at a high frequency, the STL shows dips regardless of the perforation ratios when the wavenumber and air gap depths satisfy certain conditions.While previous research has primarily concerned the dialectal influence on speakers' production of oral-nasal balance, quantitatively represented by nasalance, information on cross-dialectal variation in nasality perception is limited. This study investigated the effects of speakers'/listeners' dialectal background on oral-nasal balance characteristics estimated by nasalance, as well as nasality perception measured by direct magnitude estimation with modulus. Represented by two geographically distinct regions, Texas South and Midland dialects were of special interest given that the two dialects lie at opposite ends of normal nasalance variation [Awan, Bressmann, Poburka, Roy, Sharp, and Watts. (2015). J. Speech Lang. Hear. Res. 58, 69-77]. Mean nasalance of various speech stimuli and direct magnitude estimation ratings on synthesized vowel stimuli with varying degrees of simulated nasalization were obtained from 62 participants (31 Texas South, 31 Midland). The results revealed that the two dialectal groups significantly differed in nasalance scores and nasality ratings, with Texas South exhibiting higher nasalance for standardized passage readings and assigning higher nasality ratings on the synthetic auditory stimuli than Midland. These findings indicate that, in addition to production variations of oral-nasal balance characteristics, perceptual variations of nasality exist at a dialectal level.Noise acceptance is an aspect of indoor soundscape research. While staying or walking in a transport hub, sequential sounds form sequence sounds sessions, which are referred to as an acoustic sequence. The basic phenomenon and effects of acoustic sequences on acceptance evaluations have been explored. A total of 209 sections of 30 s acoustic units were extracted before performing acceptance evaluations. The acoustic units were divided into strong, medium, and weak levels, and compiled into 37 pieces of acoustic sequences, which were then subjected to four tests for acceptance evaluation sound content, acceptance level, and effects of weak and strong acceptance units. One piece of an acoustic sequence consists of 20 acoustic units. The results show that all acoustic sequences exhibit "attenuation effects"-as for any acoustic unit that makes up the sequence, general acceptance decreases with time. The lower the acceptance, the faster the decay in score. High acceptance units have an "enhancement effect," and the acceptance increases after a high acceptance unit. Low acceptance units have a "boost effect," and the acceptance increases after a low-level acceptance. https://www.selleckchem.com/products/d609.html Both enhancement and boost effects could improve the acceptance evaluation of acoustic sequences and sound experiences in transport hubs.The Ganong effect-more identifications of a certain phoneme in a context where that phoneme would yield a real word than a context where that phoneme would yield a pseudoword-has been widely replicated. Few studies, however, have tested whether this effect occurs for frequency contrasts. In the present study, participants' likelihood of identifying an ambiguous sound as aspirated was tested in acoustically identical continua in contexts where the identification of the sound as aspirated would either yield a lower- or higher-frequency word than the identification of the sound as unaspirated would. No frequency-based Ganong effect was found.Although the U.S. South was usually avoided for phonetic studies in earlier years, phonetic analyses of Southern U.S. English have expanded in numerous directions in recent years. Studies of vocalic variation have dominated the enterprise, with a broad range of studies that have examined the phonetic peculiarities and distribution of variants within the region, the characteristics of particular communities, and the phonetic attributes of African American and Latino groups. However, other phonetic phenomena are finally seeing more study. Several consonantal variables have attracted acoustic analysis. Other studies have focused on intonation and certain timing-related phenomena. Numerous experimental studies have tested the abilities of listeners to identify dialects and a few other perceptual issues. These developments are outlined here, including advancements in segmental, prosodic, and perceptual analyses.Interval velocities for marine sediments are generally obtained from source-receiver separations at various offsets. A method is described for estimating interval velocities using a monostatic configuration. Testing is performed using simulated data from rough layered seabeds and interval velocity is estimated within less than 1% of the true value. Monostatic multibeam data from the Gulf of Lion are also presented which exhibit many characteristics similar to the simulated data. The method applied to the measured data yield an interval velocity of 1569 m/s in an 18 m sediment layer. This accords with nearby independent data from cores and wide-angle reflection analysis.