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Access type: UnknownAuthor: search.filters.author.Danworaphong, Sorasak

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    Impact of Density and Porosity on the Sound Absorption of Binder-Free Aggregated Rice Husk
    (2025-11-01)
    Danworaphong, Sorasak
    ;
    Eadkhong, Thammarong
    This study explores the use of binder-free rice-husk aggregates, a widely available agricultural byproduct, as a sustainable alternative for sound absorption in building applications. We assessed the material’s efficacy by conducting experiments using cylindrical housings that were filled with rice husk aggregate. The aggregates were then tested in an impedance tube according to the ASTM E1050 standards in the frequency range of 400 to 6,000 Hz. The porosity was measured using an air pycnometer. The resulting average sound absorption coefficient (α<inf>avg</inf>) was modeled in terms of the porosity and the density with quadratic equations. Thus, if either property is known, α<inf>avg</inf> can be predicted. The highest recorded value of α<inf>avg</inf> was 0.81. This study underscores the environmental and practical advantages of using binder-free rice husk, especially given its local availability and the absence of binders. The findings also open avenues for sustainable construction materials and could contribute to eco-friendly noise-control applications.
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    Stokes to Hadamard-Rybczynski transition: an experimental investigation with argon bubbles rising in palm oil and a sigmoid integrated model for prediction
    (2025-10-01)
    Thida, Worakrit
    ;
    Danworaphong, Sorasak
    A refined model is developed to describe the transition in bubble dynamics from the Stokes to the Hadamard-Rybczynski regime, incorporating Bond number-dependent switch terms for predictions across a wide range of Reynolds numbers. We conduct experiments on rising argon bubbles in palm oil and use the obtained data to validate the model. We also apply the proposed model to additional data deduced from related literature to demonstrate its applicability. The analysis emphasizes the role of tangential stress at the bubble surface, governed by fluid properties, bubble size, and experimental conditions, in driving the transition. This model enhances drag prediction for a given Reynolds number and is applicable in diverse industrial contexts, including bubble column design and oil recovery. It can also be integrated into numerical simulations for complex multiphase flow analysis, supporting future advancements in multiphase system modeling and applications.
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    Development and Preliminary Evaluation of a Wireless Acoustic Sensor Network for Environmental Noise Monitoring
    (2025-01-01)
    Meesawat, Kittipitch
    ;
    Padee, Wanut
    ;
    Thida, Worakrit
    ;
    Lertsawat, Krittika
    ;
    Danworaphong, Sorasak
    This study presents the development and preliminary evaluation of a wireless acoustic sensor network (WASN) designed for environmental noise monitoring in Thailand. A WASN prototype was developed and deployed at a construction site in Bangkok. The system's performance was evaluated over 240 days, comparing its measurements to a certified Class 1 sound level meter. Preliminary results indicated that the WASN tended to report lower 1 minute A-weighted equivalent continuous sound level values than the Class 1 sound level meter with an average difference of 8 dB. The study also identified key challenges during field deployment, including downtime caused by power loss and Wi-Fi connectivity issues. Future work will focus on addressing these limitations to improve system reliability and measurement accuracy.
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    The Trapezoidal Khim: Sound Radiation of G Notes
    (2025-01-01)
    Techaaphonchai, Natcha
    ;
    Thida, Worakrit
    ;
    Meesawat, Kittipitch
    ;
    Ayuthaya, Phonlasit Thinnakorn Na
    ;
    Chitsakul, Pakaphol
    This research investigates the sound characteristics of the trapezoidal Khim, a traditional Thai hammered dulcimer, focusing on the G 196, G 392 Hz and G 784 Hz notes played with different hammers. Two types of wooden hammers were used, that is, covered with flannel and uncovered. Measurements were conducted in a room measuring 10 by 5 by 3 meters using two microphones, one for capturing the sound field directionality and the other for reference sound. The measurement microphone was placed 2 meters away from the instrument at various angles, while the reference microphone was positioned above the center of the instrument. Analysis of the recordings reveals the directivity profiles for each frequencies, showing that the Khim exhibits relatively high directivity at 90 and 270 degrees, corresponding to its open channels of the instrument. This suggests that the instrument's construction significantly influences its sound radiation. Hammer type was found to affect overall directivity, i.e., fabric-covered hammers resulted in lower directivity compared to uncovered hammers. Furthermore, the hitting point on the key significantly affects the Khim's directivity, indicating that playing technique plays a crucial role in shaping the instrument's sound projection. This study contributes to a deeper understanding of the unique sound production of the trapezoidal Khim and its role in traditional Thai music. It offers valuable information for musicians, instrument makers, and researchers interested in the acoustics of cultural instruments in realistic performance environments.
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    Phase Speed Inversion for Shallow Water Bathymetry Mapping
    (2024-01-01)
    Thida, Worakrit
    ;
    Voti, Roberto Li
    ;
    Danworaphong, Sorasak
    This study explored the use of top-view movies of propagating gravity water waves to reconstruct the underwater bed profile of shallow water bodies. Water waves of 2.8 and 3.1 Hz were generated by a microcontroller-driven flat flap in a wave flume of dimensions 0.48 × 1.80 × 0.40 m<sup>3</sup>. Three different bed profiles, i.e., sloped, stepped, and split surfaces, were used to imitate typical seabeds near shorelines. Top-view movies of the propagating waves were recorded and converted to spatial phase-speed images via video analysis. The phase speed images can be used to reconstruct the underwater bed profile using the dispersion relation of linear water waves. We also proposed a demodulation method to correct the phase-speed alteration due to wave interference. The correction method helped improve the mean average percentage error for depth profile predictions from 15% to 10% for the sloped profile and from 45% to 15% for the stepped profile. However, the approach was inferior for the split profile due to wall effects and complex interference patterns. This study suggests the proposed approach can determine the depth level around shorelines using time-evolution or video data with an adequate accuracy of 10% with minimal interference.