02041nas a2200169 4500008004100000022001400041245014400055210006900199260001600268300001600284490000800300520146900308100001401777700001401791700001501805856005101820 2019 eng d a0001-496600aA biosonar model of finless porpoise ( Neophocaena phocaenoides ) for material composition discrimination of cylinders0 abiosonar model of finless porpoise iNeophocaena phocaenoidesi fo cJan-08-2019 a1362 - 13700 v1463 a

Research into the physical mechanism of odontocetes biosonar has made great progress in the past several decades, especially on wave propagation and biosonar beam formation in the foreheads of odontocetes. Although a number of experimental studies have been performed, the physical mechanism of odontocetes underwater target discrimination has not yet been fully understood. Previous research has experimentally studied the finless porpoise's target discrimination using cylinders different in material [Nakahara, Takemura, Koido, and Hiruda (1997). Mar. Mamm. Sci. 13(4), 639–649]. The authors proposed a computed tomography based finite element biosonar model to simulate the detailed process of a finless porpoise click emission and target detection in order to gain a further understanding of the underlying physical mechanism. The numerical solutions of resonance features of both steel and acrylic cylinders in this study are very consistent with the analytic solutions. Furthermore, the simulated outgoing clicks and echoes match the experiment results measured by Nakahara et al. The beam patterns of the scattered field were extracted and the resonance features of cylinders in different materials were analyzed. This method in this study could be used to study some other odontocetes that are inaccessible for experimental work and could also provide physical information for intelligent biomimetic underwater signal processors design.

1 aFeng, Wen1 aZhang, Yu1 aWei, Chong uhttp://asa.scitation.org/doi/10.1121/1.512298101918nas a2200181 4500008004100000245017100041210006900212260001600281300001100297490000700308520123500315100002101550700001401571700001801585700001901603700001601622856009801638 2019 eng d00aInvestigation on acoustic reception pathways in finless porpoise ( Neophocaena asiaorientalis sunameri ) with insight into an alternative pathway0 aInvestigation on acoustic reception pathways in finless porpoise cJan-01-2019 a0160040 v143 a

Sound transmission and reception are both vital components to odontocete echolocation and daily life. Here, we combine computed tomography (CT) scanning and finite element modeling to investigate the acoustic propagation of finless porpoise (Neophocaena asiaorientalis sunameri) echolocation pulses. The CT scanning and finite element method wave propagation model results support the well-accepted jaw-hearing pathway hypothesis and suggest an additional alternative auditory pathway composed of structures, mandible (lower jaw) and internal mandibular fat, with different acoustic impedances, which may also conduct sounds to the ear complexes. The internal mandibular fat is attached to the ear complex and encased by the mandibles laterally and anteriorly. The simulations show signals in this pathway initially propagate along the solid mandibles and are transmitted to the acoustically coupled soft tissue of the internal mandibular fat which conducts the stimuli posteriorly as it eventually arrives at ear complexes. While supporting traditional theories, this new bone-tissue conduction pathway might be meaningful to understand the hearing and sound reception processes in a wide variety of odontocetes species.

1 aSong, Zhongchang1 aZhang, Yu1 aWang, Xianyan1 aSmith, Adam, B1 aXu, Xiaohui uhttp://stacks.iop.org/1748-3190/14/i=1/a=016004?key=crossref.cd9487fd925bb5ecdc5f0eb7a9bbb813