Université de Sherbrooke, Département de génie mécanique, Sherbrooke, Québec, J1K 2R1, Canada
Marc-André Guy, Département de génie mécanique, Université de Sherbrooke
Kamal Kesour, Innovation Maritime, Rimouski, QC, Canada
Jean-Christophe G.Marquis, Innovation Maritime, Rimouski, QC, Canada
Giuseppe Catapane, University of Naples Federico II, Naples, Italy
Giuseppe Petrone, University of Naples Federico II, Naples, Italy
Olivier Robin, Département de génie mécanique, Université de Sherbrooke
Popular version of 1pEA6 – Use of metamaterials to reduce underwater noise generated by ship machinery
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026790
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
The underwater noise generated by maritime traffic is the most significant source of ocean noise pollution. This pollution threatens marine biodiversity, from large marine mammals to invertebrates. At low speeds, the machinery dominates the underwater radiated noise from vessels. It also has a precise sound signature since it usually operates at a fixed rotation frequency. If you think of it, an idling vehicle produces a tonal acoustic excitation. The sound energy distribution is mainly concentrated at a few precise frequencies and multiples. Indeed, the engine rotates at a given rotation speed – in round per minutes – or frequency (divided by 60, it is the number of oscillations per second). In addition to the rotating frequency, the firing order and the number of cylinders will lead to the generation of excitation multiples of the rotating frequency. The problem is that the produced frequencies are generally low and difficult to mitigate with classical soundproofing materials requiring substantial material thickness.
This research project delves into new solutions to mitigate underwater noise pollution using innovative noise control technologies. The solution investigated in this work is structured quarter-wavelength acoustic resonators. These resonators usually absorb sound at a resonant frequency and odd harmonics, making them ideal for targeting precise frequencies and their multiples. However, the length of these resources is dictated by the wavelength corresponding to the target frequency. As for the required material thickness, this wavelength is significant at low frequencies (in air, for a frequency of 100 Hz and a speed of sound of 340 m/s, the wavelength is 3.4 m since the wavelength is the ratio of speed by frequency). The length of a quarter wavelength resonator tuned at 100 Hz is thus 0.85 m.
Fig.1. Comparison between classical and innovative soundproofing material on sound absorption, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Therefore, a coiled quarter wavelength resonator was considered to reduce its bulkiness, and facilitate their installation. The inspiration follows Archimedes’ spiral geometry shape, a structure easily manufactured using today’s 3D printing technologies. Experimental laboratory tests were conducted to characterize the prototypes and determine their effectiveness in absorbing sound. We also created a numerical model that allows us to quickly answer optimization questions and study the efficiency of a hybrid solution: a rock wool panel with embedded coiled resonators. We aim to combine classic and innovative solutions tom propose low weight and compact solutions to efficiently reduce underwater noise pollution!
Fig.2. Numerical model of coiled resonators embedded in rockwool, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Chemical Engineering Department, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, 382355, India
Sameer V. Dalvi – sameervd@iitgn.ac.in
Chemical Engineering Department,
Indian Institute of Technology Gandhinagar
Gandhinagar, Gujarat 382355
India
Popular version of 4pBAa3 – Ultrasound Responsive Multi-Layered Emulsions for Drug Delivery
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027523
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
What are popping droplets? Imagine you are making popcorn in a pot. Each little popcorn seed consists of a tiny bit of water. When you heat the seeds, the water inside them gets hot and turns into steam. This makes the seed pop and turn into a popcorn. Similarly, think of each popcorn seed as a droplet. The special liquid used to create popping droplets is called perfluoropentane (PFP), which is similar to the water inside the corn seed. PFP can boil at low temperatures and turn into a bubble, which makes it perfect for crafting these special droplets.
Vaporizable/Popping droplets hold great promise in the fields of both diagnosis and therapy. By using sound waves to vaporize PFP present in the droplets, medicine (drugs) can be delivered efficiently to specific areas in the body, such as tumors, while minimizing impacts on healthy tissues. This targeted approach has the potential to improve the safety and effectiveness of therapy, ultimately benefiting patients.
Figure 1. Vaporizable/popping droplets with perfluoropentane (PFP) in the core with successive layers of water and oil
What do we propose? Researchers have been exploring complex structures like double emulsions to load drugs onto droplets (just like filling a backpack with books), especially those that are water-soluble. Building on this, our study introduces multi-layered droplets featuring a vaporizable core (Fig.1). This design enables the incorporation of both water-soluble and insoluble drugs into separate layers within the same droplet. To better visualize this, imagine a club sandwich with layers of bread stacked on top of each other, each layer containing a different filling. Alternatively, picture an onion with multiple stacked layers that can be peeled off one by one. Similarly, multi-layered droplets comprise stacked layers, each capable of holding various substances, such as drugs or therapeutic agents.
To explore the features of the multi-layered droplets further, we carried out two separate studies. First, we estimated the peak negative pressure of the sound wave at which the PFP in the droplets vaporize. This is similar to how water boils at 100°C (212°F) under standard atmospheric pressure, but at low/negative pressure (like under a vacuum), water can boil at low temperatures. Sound waves are known to induce both positive and negative pressure changes. During instances of negative pressure, the pressure drops below the atmospheric pressure, creating a vacuum-like effect. This decrease in pressure can trigger the vaporization of the perfluoropentane (PFP) in the droplets at room temperatures.
Secondly, we loaded a water-insoluble drug, curcumin, which is an anti-inflammatory drug, in the oil layer and estimated the amount of drug loading (just like counting number of books in the backpack).
Figure 2. Relationship between Mean Grayscale (mean brightness) and soundwave pressure for droplet vaporization
Figure 2 depicts the relationship between the increase in mean grayscale (just like the increase in bright areas or brightness of a black-and-white picture) and the peak negative pressure of the sound wave. Based on our study, the peak negative pressure at which the PFP in the droplets was found to vaporize was 6.7 MPa. Furthermore, the loading for curcumin was estimated to be 0.87 ± 0.1 milligrams (mg), which indicates a higher drug loading capacity in multi-layered droplets.
These studies are essential because they help us determine two critical things. The first one allows us to figure out the exact sound wave pressure needed to make the droplets pop. This is useful for the controlled release of drugs in targeted areas. The second study tells us how much drug these droplets can hold, which is helpful in designing drug delivery systems.
Together, these studies enhance our understanding of multi-layered droplets and pave the way for a new targeted therapy, where popping droplets serve as vehicles for delivering drugs or therapeutic agents to specific locations upon activation by sound waves.
Beck Audio Forensics, 7618 Rockpoint Dr, Austin, Texas, 78731, United States
Popular version of 2pEA8 – Dissecting Recorded Gunshot Sounds
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027107
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Forensic audio can provide important evidence, especially when the scene information is not captured on video. Audio recordings of gunshots often supply additional information, or the only information, from a shooting incident. Analysis of the recorded audio can help determine who fired first, how many guns were fired, and sometimes identify each gunshot in a sequence. The muzzle blast, or “bang”, and the ballistic shockwave, or “crack” from a supersonic bullet are the most common sounds analyzed. These very loud sounds often obscure other gunshot sounds that can provide important forensic evidence. New recording technology, like floating point recorders and high sensitivity police body cameras, may capture multiple acoustic sound sources from a gunshot, depending on the shooting, propagation, and recording conditions.
In order to investigate the multiple sounds from a gunshot, a body camera and Zoom F6 multi-channel floating point recorder were used to record gunshot sounds using microphones placed at 90o, 135o, and 180o relative to the line of fire. Revolvers, semiautomatic pistols, and long barrel firearms (rifles and shotguns) are shown to have different sequences of acoustic source events:
Revolver have the primer blast, chamber gas jet, muzzle blast, mechanical sounds
Pistols have the primer blast, muzzle blast, slide/bolt sound, mechanical sounds
Semiautomatic rifles have primer blast, slide/bolt sound, muzzle blast, mechanical sounds
Bold action rifles have primer blast, muzzle blast, later mechanical sounds
Figure 1 shows an example of multiple acoustic sources in a gunshot. The left side plots show a muzzle blast followed by a mechanical sound. Zooming in on the amplitude shows a much quieter primer blast that occurs before the muzzle blast. The bottom right plot is the same gunshot recorded on a police-style body camera. The primer blast is very clear, but the other gunshot sounds are clipped. Since the primer blast can only be recorded behind or to the side of a close-by shooter, it’s presence in a recording can help determine “who fired first” or help identify individual gunshots.
Figure 1 – A Primer Blast Prior to the Muzzle Blast Indicates the Presence of a Near-by Shooter
In addition to blast-related sounds, there are sounds related to ballistics. Recording these sounds are very position dependent, and require the recording system to be close to the source. These sounds include the ballistic shockwave and ballistic flow sound (recorded close to a passing bullet), tumbling bullet, reverberation and reflections, and the ballistic impact. Ballistic sounds can help identify a gunshot or a possible shooting location.
Michael Kundakcioglu – mkundakcioglu@hgcengineering.com
HGC Engineering, 2000 Argentia Road, Plaza One, Suite 203, Mississauga, Ontario, L5N 1P7, Canada
Jessica Tinianov
Adam Doiron
Popular version of 1aAA9 – Sound flanking through common low-voltage electrical conduit in multi-family residential buildings
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026642
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Residents living in an apartment or condominium expect a certain amount of privacy, especially when it comes to noise intrusions from neighbours. In fact, there are Building Code requirements in most jurisdictions which outline minimum requirements for the design of suite-demising architectural assemblies, to limit the allowable amount of sound that can go directly through (or in some cases, around) walls, floors, and ceilings. Despite this, sometimes, noise finds a way to travel through the building in unexpected ways, sometimes bypassing these assemblies. One such “sneaky” path is through the electrical conduits – those tubes that carry electrical wires between suites.
These conduits can act like a highway for sound, especially if they’re not sealed properly at certain points, like where they connect to fire alarms. This can allow noise from one suite to easily travel to another, even if the walls are properly designed to block sound. It’s a bit like having string from one suite to another, tied to a foam cup on each side, like those makeshift telephones we used to make as children.
This isn’t just a minor annoyance; it can be a big problem. In fact, this conduit issue has been found in multiple buildings in recent times, and it can reduce the effectiveness of the walls that are meant to keep sound in – by quite a bit. In many cases, this simple flaw in construction can cause the sound transmission between suites to fail Building Code requirements mentioned above, depending on the local requirements.
The good news is that this can be prevented. Sealing the open holes at the end of the conduits with simple flexible caulking on both sides of the tube greatly reduces the amount of noise from traveling through them (see Figure 1 below). It’s a simple solution that can make a big difference in the level of noise intrusion between suites.
Figure 1: Unsealed Conduit Opening in Fire Alarm Junction Box (Left), and Conduit Opening after Applying Sealant (Right). Image Courtesy of HGC Engineering
Standard sound transmission testing (known as Apparent Sound Transmission Class or ASTC testing) has shown that sealing these conduits can reduce the amount of sound travelling through the conduit so much that the amount of sound transmitted from suite-to-suite returns to the expected design values. In Figures 2 and 3 below, we plot the amount of sound transmitted between two adjacent suites as tested in four different real-world buildings with three different wall types separating the suites (double steel stud walls in Figure 2, and poured concrete walls in Figure 3); the dotted lines represent the amount of sound blocked by the wall when the conduit routed between the suites is left unsealed, while the solid lines represent the amount of sound blocked when the conduit has been sealed with caulking.
Figure 2: Steel Stud Walls Transmission Loss Results, as Tested by HGC Engineering
Figure 3: Poured Concrete Walls Transmission Loss Results, as Tested by HGC Engineering
In the above tests, we see the ASTC rating increase by 5 to 10 points once the conduits are sealed, which is a significant and very noticeable difference. In conclusion, if you are a developer, builder, architect, or engineer, it might be worth looking into whether the conduits in the suites in your buildings are properly sealed. It’s a fix that can help everyone get back to enjoying their own space in peace.
Dick Botteldooren and Paul Devos
Ghent University
Technology Campus, iGent, Technologiepark 126
Gent, Gent 9052
Belgium
Popular version of 2aNSb7 – Soundscape Augmentation for People with Dementia Requires Accounting for Disease-Induced Changes in Auditory Scene Analysis
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026999
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Sensory stimuli are significant in guiding us through space and making us aware of time. Sound plays an essential role in this awareness. Soundscape is an acoustic environment as perceived and experienced by a person. A well-designed soundscape can make the experience pleasant and improve moods; in contrast, an unfamiliar and chaotic soundscape can increase anxiety and stress. We aim to discuss different auditory symptoms of dementia and introduce ways to design an augmented soundscape to foster individual auditory needs.
People with dementia suffer from a neurodegenerative disorder that leads to a progressive decline in cognitive health. Behavioural and psychological symptoms of dementia refer to a group of noncognitive behaviours that affect the prediction and control of dementia. Reducing the occurrence of these symptoms is one of the main goals of dementia care. Environmental intervention is the best nonpharmacological treatment to improve the behaviour of people with dementia.
People with severe dementia usually live in nursing homes, long-term care facilities, or memory care units where sensory perception is unfamiliar. Strange sensory stimuli add to residents’ anxiety and distress, as care facilities are often not customized based on individual needs. Studies show that incorporating pleasant sounds into the environment, known as an ‘augmented soundscape,’ positively impacts behaviour and reduces the psychological syndrome of dementia. Sound augmentation can also help a person navigate through space and identify the time of the day. By implementing sound augmentation as part of the design, we can enhance mood, reduce apathy, lower anxiety and stress, and promote health. People with dementia experience changes in perception, including misperceptions, misidentifications, hallucinations, delusions, and time-shifting. Sound augmentation can support a better understanding of the environment and help with daily navigation. In the previous study by the research team, implementing soundscape in nursing homes and dementia care units showed a promising result in reducing the psychological symptoms of dementia.
It’s crucial to recognize that dementia is not a singular entity but a complex spectrum of degenerative diseases. For example, environmental sound agnosia—the difficulty in understanding non-speech environmental sounds—is common in some with frontotemporal dementia. Therefore, sound augmentation should be focused on non-complicated sounds. Amusia, another type of dementia, is when a person cannot recognize music; thus, playing music is not recommended for this group.
Each type of dementia presents with its unique set of symptoms, including a variety of auditory manifestations. These can range from auditory hallucinations and disorientation to heightened sound sensitivity, agnosia for environmental sounds, auditory agnosia, amusia, and musicophilia. Understanding these diverse syndromes of auditory perception is critical when designing a soundscape augmentation for individuals with dementia.
Fig.1. Comparison between classical and innovative soundproofing material on sound absorption, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Figure 1. Vaporizable/popping droplets with perfluoropentane (PFP) in the core with successive layers of water and oil
Figure 2. Relationship between Mean Grayscale (mean brightness) and soundwave pressure for droplet vaporization
Figure 1 – A Primer Blast Prior to the Muzzle Blast Indicates the Presence of a Near-by Shooter
Figure 1: Unsealed Conduit Opening in Fire Alarm Junction Box (Left), and Conduit Opening after Applying Sealant (Right). Image Courtesy of HGC Engineering
Figure 2: Steel Stud Walls Transmission Loss Results, as Tested by HGC Engineering
Figure 3: Poured Concrete Walls Transmission Loss Results, as Tested by HGC Engineering