A Study of Speed of Sound in Water

Kumar, Anuj; Pathak, Pankaj; Dass, N. D. Hari

doi:10.9790/4861-0804022123

Cited by 6 publications

(2 citation statements)

References 13 publications

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“…An increase in moisture content in wood causes the velocity of sound transmission to decrease (Sandoz 1989;Unterwieser and Schickhofer 2011;Montero et al 2015); however, this clearly applies to the longitudinal direction only. Taking into account that the speed of sound in water at room temperature is approximately 1500 m/s (Kumar et al 2016) and the speed of sound wave propagation perpendicular to the fibres (in the radial direction) is in the range of 1000 to 2000 m/s (Divos and Divos 2005), the presence of free water in wood may significantly influence the propagation speed of acoustic waves.…”

Section: Introductionmentioning

confidence: 99%

Comparison of variability in results of acoustic tomographs in pedunculate oak (Quercus robur L.)

Cristini

Tippner

Vojáčková

et al. 2021

BioRes

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Tree acoustic tomography is a widely used device supported method for tree stability assessment. In this work, the results of the three most commonly used devices for acoustic tomography of standing trees (ARBOTOM®, ArborSonic®, and PiCUS®) were compared on selected individuals of sessile oak in Brno, Czech Republic. According to the statistical analysis, there was a significant difference between values measured by the PiCUS® acoustic tomograph and those measured by both the ARBOTOM and ArborSonic® acoustic tomographs. Based on the measured data, velocities measured by PiCUS® were considerably lower than those recorded by the other acoustic tomographs (ARBOTOM® and ARBORSONIC®). Measured radial and tangential velocities differed from each other. In data obtained from the defective cross-sections, this difference was attenuated. Image reconstructions (tomograms) from the acoustic tomographs differed from each other. Complex shapes of defects in standing trees can significantly influence acoustic tomography results. According to the statistical analysis, there was no significant relationship between sound velocity and density, while there was a relatively strong positive correlation between sound velocity and moisture content.

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Section: Introductionmentioning

confidence: 99%

Comparison of variability in results of acoustic tomographs in pedunculate oak (Quercus robur L.)

Cristini

Tippner

Vojáčková

et al. 2021

BioRes

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“…Another facet of the acoustic underwater channel is the extremely high propagation delay of the signals. While RF waves travel at the speed of light, roughly 300,000 km/s [9], acoustic signals propagate underwater at roughly 1.5 km/s in 10-20 • C conditions [10]. This can serve as a roadblock for developing and efficient MAC scheme which relies on round-trip time or is otherwise accessed based on a shared time domain (TDMA).…”

Section: Overview Of Internet Of Underwater Things Systemsmentioning

confidence: 99%

Software-defined acoustic underwater mesh networks

Turco

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While terrestrial IoTs have been extensively explored, both academically and commercially, IoUTs have had significantly fewer developments. The underwater channel presents unique challenges which cause commonly utilized communication methodologies in the RF domain to become nonviable. This thesis presents an underwater mesh network designed to address the challenges faced in the network, data link, and physical layers of the underwater acoustic domain. This underwater mesh network implements a proactive routing protocol for maintaining routing topology, allowing for Dijkstra's algorithm to be utilized as an efficient method of determining the next hop for a data packet. Endpoints across an on-board Ethernet socket will be capable of joining the mesh network, allowing for cross-medium data forwarding. A CRC-32 was implemented as the primary methodology for error detection. Two MAC schemes were implemented for this underwater mesh network: a Pure ALOHA scheme and a repetitive burst retransmission scheme. The routing table discovery process and the implemented MAC schemes were evaluated through testing with hardware in a real-world oceanic environment (located in the Boston harbor). Utilizing a ZP-OFDM communication scheme, the underwater mesh network's discovery process was able to establish topological consensus on the state of the routing table quickly and accurately in this real-world setting. The repetitive retransmission scheme greatly outperformed the Pure ALOHA scheme due to the greater number of collisions (from acknowledgement packets in the shared channel) in the Pure ALOHA scheme. Through real-world testing, the protocols and systems implemented within this underwater mesh networks were shown to be highly successful at establishing and maintaining a network at varying levels of data traffic.

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Acoustic tomography outputs in comparison to the properties of degraded wood in beech trees

et al. 2022

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The interpretation of the outputs of acoustic tomography is often altered by different physical and mechanical parameters. Detailed information on the relationships between static mechanical properties and dynamic parameters of intact and degraded green wood can improve the results of this device-supported method used for tree stability assessment. This research presents a graphic and statistic comparison of acoustic tomography outputs with the laboratory assessed material parameters. The analysis was based on the relationship between the dynamic and static mechanical parameters of four cross-sections from two living tree stems. The occurrence of seven white and soft rot fungi was taken into consideration. The influence of density ($$\uprho$$ ρ ) on stress-wave propagation ($$v$$ v ) was proved. A strong correlation between the dynamic moduli of elasticity ($${E}_{dyn}$$ E dyn ) and compressive strength ($$\upsigma$$ σ ) is reported. A higher heterogeneity of wood degradation among the cross-section can lead to an underestimation of the defect during AT assessment. The dynamic modulus of elasticity $${E}_{dyn}$$ E dyn was less influenced than $$v$$ v by the heterogeneity of degraded wood. Therefore, $${E}_{dyn}$$ E dyn can be used to form a better interpretation of acoustic tomography assessment of standing beech trees. Due to the complexity of the topic, further investigation of previously mentioned relationships is still needed.

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A Study of Speed of Sound in Water

Cited by 6 publications

References 13 publications

Comparison of variability in results of acoustic tomographs in pedunculate oak (Quercus robur L.)

Comparison of variability in results of acoustic tomographs in pedunculate oak (Quercus robur L.)

Software-defined acoustic underwater mesh networks

Acoustic tomography outputs in comparison to the properties of degraded wood in beech trees

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