|
| ||
|
|
||
Acoustic Characteristics (acoustic + characteristic)
Selected AbstractsAcoustic characteristics of high damping Mn73Cu20Ni5Fe2 alloyPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2004M. Fukuhara Abstract The acoustic characteristics for high damping Mn73Cu20Ni5Fe2 (M2052) alloy were investigated in terms of frequency-dependent complex dynamics, using an ultrasonic pulse method. The longitudinal and transverse waves show maximum decrements of about 2 and 1.8 at around 1.8 and 0.8 MHz, respectively, derived from a single relaxation process. Frequency dispersion leads to increase in dynamic modulus and delay in phase, suggesting growth (microkinking) of microtwin phases analogous to the stretching by micro-Brownian rotation in rubbers. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Vocal Discrimination in Mate Guarding Male Australian Sea Lions: Familiarity Breeds ContemptETHOLOGY, Issue 8 2010Marie R. G. Attard The vocal characteristics of a species can be immensely diverse, and can significantly impact animal social interactions. The social structure of a species may vary with geographical variation in call characteristics. The ability of pinnipeds (true seals, fur seals, sea lions and walrus) to distinguish between conspecifics may assist male reproductive strategies, particularly mate acquisition. We assessed the ability of mate guarding Australian sea lion (Neophoca cinerea) males to discriminate local from foreign males' barks recorded from a geographically distant breeding colony. Bark characteristics were significantly different between colonies, with barks produced by males from the Lewis Island breeding colony higher pitched and longer in both duration and interval duration than barks produced by males on Kangaroo Island. Mate guarding males displayed inter-colony discrimination of barks, with a significantly stronger response to barks from local males than to those of males from a colony approx. 180 km away. Local males' barks were apparently considered a greater threat than barks from unfamiliar males. We propose that discrimination of acoustic characteristics may facilitate reproductive isolation in this species that may lead to an ethological,acoustic barrier between breeding colonies, and subsequent genetic isolation. [source] Acoustic measurement of intake and grazing behaviour of cattleGRASS & FORAGE SCIENCE, Issue 2 2000Acoustic analysis of grazing behaviour was found to allow accurate identification of chewing and biting, and estimation of intake by cattle. Four steers grazed six types of turves, three were short (14, 16 and 20 cm tall), leafy turves from mowed Setaria lutescens with high application of N fertilizer, and three were tall (36, 49 and 62 cm tall), mature turves from uncut areas with low application of N fertilizer. Each animal grazed ten bites from each turf type while behaviour was videotaped and grazing sounds were recorded with a wireless microphone taped to the animal's forehead. The intake was measured by the difference in pre- and post-grazing turf weight, corrected for water loss. Chews and bites differed in acoustic characteristics, with bites producing more output in the 3,8 kHz frequency band. Discriminant analysis of the acoustic characteristics correctly classified chews and bites with 94% accuracy. Intake was predicted with a high degree of accuracy by total energy flux density (fJ m,2) in chewing sounds (EFDC), EFDC per chew and average intensity of chewing sound in the 1,2 and 2,3 kHz bands (R2=0·90, CV=3·6%). Although bite mass ranged from 1·37 to 4·50 g, EFDC per g of intake (CV=0·015) was not affected by treatments or animals. Chewing sounds carried more information about intake than biting sounds and chews per bite. Analysis of grazing sounds has the potential to overcome many of the problems associated with the measurement of grazing intake. [source] Whining as mother-directed speechINFANT AND CHILD DEVELOPMENT, Issue 5 2005Rosemarie I. Sokol Abstract Although little studied, whining is a vocal pattern that is both familiar and irritating to parents of preschool- and early school-age children. The current study employed multidimensional scaling to identify the crucial acoustic characteristics of whining speech by analysing participants' perceptions of its similarity to other types of speech (question, neutral speech, angry statement, demand, and boasting). We discovered not only that participants find whining speech more annoying than other forms of speech, but that it shares the salient acoustic characteristics found in motherese, namely increased pitch, slowed production, and exaggerated pitch contours. We think that this relationship is not random but may reflect the fact that the two forms of vocalization are the result of a similar accommodation to a universal human auditory sensitivity to the prosody of both forms of speech. Copyright © 2005 John Wiley & Sons, Ltd. [source] A comparison of three noise reduction procedures applied to bird vocal signalsJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2007Myron C. Baker ABSTRACT Recordings of avian vocal signals in natural habitats include ambient noise. Often this background noise corrupts across all frequencies and is of substantial amplitude. Reducing this ambient noise to prepare vocal signals for playback stimuli or to remove habitat-specific noise signatures prior to analyzing a signal's acoustic characteristics can be useful. We conducted experimental evaluations of three noise reduction procedures to determine their effectiveness. We embedded two bird vocalizations ("clean" signals) in four kinds of natural noise, resulting in eight noise-signal combinations. We then applied three noise reduction procedures (Noise Profile, Band Pass, and Noise Estimate) to each of the embedded signals and compared the recovered signals to the original (clean) signals. Noise Profile filtering was effective in reducing noise and returning fairly high-quality signals from even severe levels of masking noise. The other two noise reduction procedures did not perform as well. For the two most corrupting maskers, however, Noise Profile filtering also altered the signal properties by reducing signal amplitude at those frequencies containing high levels of noise. Apart from this loss of amplitude, the quantitative features of the filtered signals were similar to those of the original model sounds. We conclude that Noise Profile filtering produces good results for cases where noise is approximately constant over the signal duration and the signal intensity exceeds noise intensity over the frequencies of interest. SINOPSIS La grabación de sonidos de aves en hábitats naturales incluye ruidos ambientales. A menudo este ruido es de amplitud sustancial y afecta todas las frecuencias. Antes de analizar una señal vocal, podría ser útil reducir este ruido ambiental, bien para preparar vocalizaciones grabadas para provocar respuestas de aves como para remover ruidos asociados a hábitats. Llevamos a cabo una serie de experimentos con tres procedimientos de reducción de ruido para determinar su efectividad. Insertamos dos vocalizaciones de aves (señales "limpias") en cuatro tipos de ruidos naturales, obteniendo como resultado ocho combinaciones de señales con ruido. Posteriormente, aplicamos tres procedimientos de reducción de ruido ("Perfil de Ruido,""Paso de Banda" y "Estimaciones de Ruido") a cada una de las señales insertadas y comparamos las señales recuperadas con los sonidos originales (limpios). La filtración tipo "Perfil de Ruido" resultó efectiva para reducir el ruido y producir señales de razonablemente buena calidad, aún en situaciones de ruido severo. Los otros dos tratamientos no funcionaron tan bien. Para los dos tipos de ruido con mayores efectos, el "Perfil de Ruido" alteró las propiedades de la señal y redujo la amplitud de la misma, en aquellas frecuencias que contenían altos niveles de ruido. Además de la pérdida de amplitud, los elementos cuantitativos de las señales filtradas fueron similares a las de los modelos sonoros originales. Concluimos que el procedimiento de filtrado "Perfil de Ruido" produce buenos resultados para casos en donde el ruido es de duración aproximadamente constante a lo largo de la señal y cuando la intensidad de la señal excede la intensidad del ruido sobre las frecuencias de interés. [source] Temperature dependence of elastic parameters and internal frictions for MnCu20Ni5Fe2 alloyPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2004Mikio Fukuhara Abstract Using ultrasonics, MnCu20Ni5Fe2 (M2052) alloy's acoustic characteristics were observed in order to understand its high damping properties. Longitudinal and shear wave velocities, eight kinds of elastic parameters, and dilational and shear internal frictions were simultaneously measured as functions of temperature in cooling and heating runs between 218 and 373 K in M2052 alloy. A valley in Young and shear moduli, Debye temperature and internal friction peaks at around 345 K showed a M2052 fcc/fct trans-formation, accompanied by volume-nonpreserving lattice softening. The increment of dilational friction in the low temperature can be interpreted as boundary effect of the misfit domain, associated with nonharmonity of potential between pairs of atoms. The M2052 alloy shows highest elasticity below 300 K, indicating large resistance for volume-preserving distortion. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||