Acoustofluidics, the integration of acoustics and microfluidics, is a rapidly growing research field that is addressing challenges in biology, medicine, chemistry, engineering, and physics. In particular, acoustofluidic separation of biological targets from complex fluids has proven to be a powerful tool due to the label-free, biocompatible, and contact-free nature of the technology. By carefully designing and tuning the applied acoustic field, cells and other bioparticles can be isolated with high yield, purity, and biocompatibility. Recent advances in acoustofluidics, such as the development of automated, point-of-care devices for isolating sub-micron bioparticles, address many of the limitations of conventional separation tools. More importantly, advances in the research lab are quickly being adopted to solve clinical problems. In this review article, we discuss working principles of acoustofluidic separation, compare different approaches of acoustofluidic separation, and provide a synopsis of how it is being applied in both traditional applications, such as blood component separation, cell washing, and fluorescence activated cell sorting, as well as emerging applications, including circulating tumor cell and exosome isolation. Research into using sound waves to separate biological particles from fluid moving through tiny channels is rapidly advancing, but more is needed to develop real-life clinical applications. Tony Jun Huang of Duke University in the US and colleagues reviewed the latest studies in the rapidly growing field of ‘acoustofluidic separation’. While progress has been made in using the technology to separate micro-sized objects like cells and bacteria from fluids, few breakthroughs have been achieved for separating nanoparticles, like lipids and viruses. Also, advances are needed to speed up the separation process. Still, the field shows much promise for the development of label-free, point-of-care devices for cancer diagnosis, placental health monitoring, and isolating bacteria from water or food. Focusing on product development and technological improvements will enable this technology to find real-world applications, the researchers conclude.
The problem of low-frequency noise is becoming increasingly severe and measuring the sound absorption performance of acoustic metamaterials (AMs) using accurate absorption coefficients is of great interest in low-frequency noise control engineering. Conventional calculation methods such as Finite Element Method (FEM) simulations and the theoretical analysis methods (TAM) have specific limitations. Deep learning (DL) models provide new perspectives for studying AMs acoustic performance. However, the prediction performance of DL models is highly dependent on the proper tuning of hyperparameters. As far as is known, existing literature has not systematically explored the impact of hyperparameter tuning on DL models in the context of acoustic performance studies. The present paper designed a multi-dimensional Helmholtz resonator (MDHR) consisting of a 4 × 4-type continuous parallel arrangement, while a dataset was established via FEM. Furthermore, a deep neural network (HPO-DNNs) model based on hyperparameter optimization (HPO) was proposed to predict the acoustic performance of the MDHR. Random search (RS), Bayesian optimization (BO), Simulated annealing (SA), and genetic algorithm (GA) were introduced to optimize the hyperparameters (learning rate, weight decay, optimizer, and batch size) of the DNNs. The mean square error (MSE), coefficient of determination (R2) of the testing dataset and the optimization time were used as the evaluation metrics, GA was selected for further study based on the comparison results (MSE = 0.00177, R2 = 0.98151) of the optimization efficiency and predictive precision of DNNs from the four HPO algorithms. Finally, the prediction performance of the GA-DNNs model was evaluated in single-, multi-, and broadband conditions in practical applications, demonstrating high precision and stability and providing a new approach for acoustics performance studies.
The present study compares the behavior of different sound types and their sources concerning distance. Experimental findings demonstrate a consistent reduction in noise levels with increasing distance from the sound origin, aligning with anticipated sound propagation patterns. Median noise level reductions are quantified, showing decreases from 72.7 dB at the source to 54.8 dB at a distance. Pulsed sounds exhibit pronounced fluctuations and peaks at close distances, while steady and blended sounds maintain more uniform levels. An exponential model accurately characterizes the noise reduction phenomenon (R² = 0.8664), underscoring its relevance for noise management, urban planning, and acoustic engineering applications. These results offer valuable insights into sound propagation dynamics and provide a basis for developing effective noise control strategies and optimizing environmental acoustics.
High noise levels in hospitals pose risks to both patients and staff, inducing stress, discomfort, and restlessness. This study presents results from a noise survey conducted in a Dhaka teaching hospital, revealing daytime levels ranging from 48 to 63 dB LAeq, exceeding Bangladesh standards. Noise levels correlated with ward layout and sources, not patient demographics. Strategies such as noise reduction, acoustic materials, and staff/patient programs can improve hospital acoustics effectively. This study reviews research from multiple disciplines including medicine, psychology, architecture, and acoustics, focusing on topics such as hospital noise, sleep quality, patient privacy, and music therapy. Findings indicate hospitals often exceed recommended noise levels, negatively impacting patients and staff with sleep problems, higher blood pressure, and burnout. Poorly designed sound environments compromise patient privacy and communication. Strategies like private rooms, sound-absorbing materials, and music therapy are recommended to reduce noise levels and improve communication. To enhance patient confidentiality, private rooms with sound-blocking features are suggested. Overall, the study underscores the importance of sound management in healthcare and advocates for design strategies to mitigate noise-related issues while ensuring effective communication. KEY WORDS: Noise, patient, acoustic, healthcare, hospital.
The method using a time-stationary reference sound source is effective in various measurements in architectural acoustics and noise control engineering. Similarly, the method using impulsive reference sound source is worth considering as an acoustic measurement technique. In this paper, "sound energy level" for an impulsive sound source is firstly introduced as an acoustic quantity corresponding to "sound power level" of a stationary sound source. (The measurement methods of this quantity are described in the appendix.) Based on the concept, the applications of an impulsive reference sound source to such acoustic measurements as "strength" (sound pressure level distribution in a room), equivalent sound absorption area in a room and sound power level of a sound source are investigated theoretically and experimentally.
Vincenzo Pettoni Possenti, E. Maccaferri, G. Fusaro
et al.
Nanofibrous membranes show interesting mechanical properties, low thickness and lightness, besides the possibility of using a great variety of polymers. The electrospinning technique makes possible the production of polymeric random nanofibres to form nonwoven membranes, which are currently used in several application fields, such as filtration, biomedicine, biomechanics, electronics, and composite materials. Their application in the automotive and aerospace engineering field could bring significant benefits to the acoustic comfort design. However, their acoustics properties still need to be further assessed. This study investigates the acoustic absorption of electrospinning-made nanofibrous membranes in Nylon 66 with different fibre diameters and mat thicknesses. Morphological and thermal characterisation of the electrospun membranes have been assessed via Scanning Electron Microscope (SEM) and Differential Scanning Calorimetry (DSC), respectively. The acoustic absorption characteristics of various samples changing fibre diameter, membrane thickness and mounting conditions were tested in the impedance tube. The results showed more relevant acoustic absorption properties in the nanofibrous membrane coupled with a polyester fibre. Further studies will clarify if filament direction and constituent material can be improved for a more durable and resistant membrane application.
This study focuses on enhancing the accuracy of engineering vehicle identification through the optimization of acoustic characteristics and the use of the UBM-GMM algorithm, aiming to reduce the operation time of the identification process and thereby better prevent underground cable damage. The research compared three types of features: traditional MFCC features, combined feature M1, and optimized feature M2. The results indicated that the optimized feature M2 achieved a recognition accuracy of 94%, with the shortest training and recognition times being 127.017 seconds and 0.86 seconds, respectively. An AUC evaluation of 0.94 demonstrates the model’s strong recognition performance. The study validated the effectiveness of vibration acoustics recognition technology based on optimized acoustic properties in improving the identification rate of engineering vehicles and shortening the recognition time, providing crucial technical support for the timely protection of underground cables.
Abstract The increased use of face masks for infection prevention has resulted in difficulties in speech understanding. Thus, there is a need for tuning of acoustic plans in hearing aids to compensate for the loss of acoustic information due to the mask.Previous studies focused on isolated vowel sounds. Our study measured the effect of surgery masks on the acoustic attributes of vowels and compared the effect of isolated to co-articulated vowels. The voices of 45 male speakers were recorded whilst pronouncing isolated vowels and vowels within the co-articulation in a sentence. All recordings were repeated with the participants wearing a surgical mask. Acoustic factors of length, intensity, pitch, formants, shimmer, and jitter were extracted from the vowels in all the different conditions. The differences between masked and unmasked acoustics in the co-articulated vowels were found to be smaller than the isolated vowels acoustic features. These preliminary results improve the quantification of the effect of hearing a face mask in the real-life production of speech.
Vibration analysis is fundamental in the analysis and design of rotating machinery designs, such as turbines, pumps and bearings. It is equally important in the theory of sound and is also related to the properties of electromagnetic waveguides. Its application extends to vehicle structures, equipment and design machines, both for reference and comfort. However, a vibrational analysis also has more daring purposes, directed to the definition of seismic attributes, to the dispersion of phenomena related to acoustics in infinite media. This solution can be adapted as the frequency of vibrations and how outdoor environments are designed for self-balancing devices are designed for Helmholtz self-balancing devices, which are directly adjusted. Typical pressure media situations, Boundary Element Method (BEM) is considered as one of the technical circumstances or more considered, due to its pressure field accuracy, especially differentiated by barriers and scattering of general circumstances, whose frequencies are complex numbers. This work aims to present the various particularities of BEM in approaching these problems, which involve determining the acoustic eigenvalues in open and closed domains, highlighting its operational advantages and numerical difficulties.
In his doctoral research Tony Embleton studied nonlinear acoustics experimentally using techniques available in the Physics Department of Imperial College, University of London. Originally developed by V. Timbrell, the interferometric equipment was substantially improved by Tony Embleton, enabling his Ph.D. findings. Studying propagation in a tube and reflection by both closed and open ends, Tony Embleton was able to substantially confirm the theory of the time, developed by Stokes, Earnshaw, Rankine, Rayleigh, and Taylor, many pieces confirmed for the first time. He also found discrepancies regarding the attenuation coefficients regarding the first and second half cycle of each pulse as well as a shortening of a pulse at reflection from a closed end. These findings are still worthy of further investigation. The results of reflection of pulses from the open end of a tube, forming a pressure release boundary condition, still are very interesting to the present author. A pulse propagating toward the open end steepens, but the reflected wave “unsteepens” which is a unique nonlinear acoustic phenomenon. [Work supported by the Penn State College of Engineering and its United Technologies Corporation Professorship.]
: Since its inception in 2004, nested sampling has been used in acoustics applications. This work applies nested sampling within a Bayesian framework to the detection and localization of sound sources using a spherical microphone array. Beyond an existing work, this source localization task relies on spherical harmonics to establish parametric models that distinguish the background sound environment from the presence of sound sources. Upon a positive detection, the parametric models are also involved to estimate an unknown number of potentially multiple sound sources. For the purpose of source detection, a no-source scenario needs to be considered in addition to the presence of at least one sound source. Specifically, the spherical microphone array senses the sound environment. The acoustic data are analyzed via spherical Fourier transforms using a Bayesian model comparison of two different models accounting for the absence and presence of sound sources for the source detection. Upon a positive detection, potentially multiple source models are involved to analyze direction of arrivals (DoAs) using Bayesian model selection and parameter estimation for the sound source enumeration and localization. These are two levels (enumeration and localization) of inferential estimations necessary to correctly localize potentially multiple sound sources. This paper discusses an efficient implementation of the nested sampling algorithm applied to the sound source detection and localization within the Bayesian framework.
This research explores the potential of acoustic fabric in architecture, focusing on its ability to enhance sound quality, improve acoustics, and contribute to the overall design aesthetics and functionality of architectural spaces. The study investigates various aspects of acoustic fabric, including its composition, manufacturing processes, acoustic properties, and application techniques in architectural design. Through a comprehensive review of literature, case studies, and empirical analysis, this research aims to provide insights into the benefits and challenges of using acoustic fabric in architectural projects. The findings of this study will contribute to a deeper understanding of how acoustic fabric can be effectively integrated into architectural design to create more comfortable and functional spaces. KEYWORDS: fabric innovation, interior architecture,acoustic fabric .
Abstract Thermoacoustic engines, a promising technology at the intersection of thermodynamics and acoustics, offer a novel and sustainable method for recovering waste heat from various industrial processes. This paper explores the principles of thermoacoustic engines and their potential application in waste heat recovery systems. By converting waste heat into useful mechanical work through acoustic phenomena, thermoacoustic engines contribute to energy efficiency and greenhouse gas reduction. This abstract summarizes the key concepts, benefits, and challenges associated with thermoacoustic waste heat recovery, emphasizing its role in addressing environmental concerns and advancing sustainable energy practices.