Sound Properties Research Articles

Connecting Artificial Intelligence and Structural Glass Engineering – Overview, Potentials and Case Studies

This paper introduces the Artificial Intelligence (AI) technology to structural glass engineering and glass industry audience. The first part of the paper is concerned with lying nomenclature and theory foundation of AI and its subclasses of Machine and Deep Learning (ML/DL), elaborating the specific needs and requirements for the application in a structural glass context. A subsequent section explores applications of AI for different subjects within the production and quality assessment of glass products as well as the design, verification and monitoring of facades and glass structures. This paper presents successfully conducted industry projects by the authors, which are: supervised ML for material parameter identification of polymeric interlayers used in laminated glass, the prediction of sound insulation properties of insulation glass units and glass laminates and the application of computer vision DL methods to image classification of the Pummel test. A visionary outlook highlights how to use AI for future generative design and verification of glass structures for rapid collaborative prototyping. The summary and conclusion section wraps up the main findings for the applicability and impact of AI for the presented structural glass research and industry problems. This paper shows, that already by today in many cases AI, data, software and computing resources are already in place to successfully implement and conduct AI projects in the glass industry and structural glass engineering practice.

A reliability study concerning the acoustic simulations of timber elements for buildings

Engineered wood constructions and timber buildings are rapidly developing, while the numerical techniques usable for their sound insulation properties are various and often still under development. This research constitutes a first step towards the reliability determination of building acoustics simulations on timber-based elements. A small scale round robin involving five research laboratories is presented. The results obtained show significant deviations depending on the chosen numerical method and indicate how laboratory measurements could not be approximate with a good accuracy. Finally, a sensitivity analysis is presented and challenges as well as requirements for reliable timber structures acoustic predictions are discussed.

Grain size dependent high-pressure elastic properties of ultrafine micro/nanocrystalline grossular

We have performed sound velocity and unit cell volume measurements of three synthetic, ultrafine micro/nanocrystalline grossular samples up to 50 GPa using Brillouin spectroscopy and synchrotron X-ray diffraction. The samples are characterized by average grain sizes of 90 nm, 93 nm and 179 nm (hereinafter referred to as samples Gr90, Gr93, and Gr179, respectively). The experimentally determined sound velocities and elastic properties of Gr179 sample are comparable with previous measurements, but slightly higher than those of Gr90 and Gr93 under ambient conditions. However, the differences diminish with increasing pressure, and the velocity crossover eventually takes place at approximately 20–30 GPa. The X-ray diffraction peaks of the ultrafine micro/nanocrystalline grossular samples significantly broaden between 15–40 GPa, especially for Gr179. The velocity or elasticity crossover observed at pressures over 30 GPa might be explained by different grain size reduction and/or inhomogeneous strain within the individual grains for the three grossular samples, which is supported by both the pressure-induced peak broadening observed in the X-ray diffraction experiments and transmission electron microscopy observations. The elastic behavior of ultrafine micro/nanocrystalline silicates, in this case, grossular, is both grain size and pressure dependent.

A light-weight periodic plate with embedded acoustic black holes and bandgaps for broadband sound radiation reduction

Conceiving lightweight structures with low vibration and sound radiation properties is an important topic. The concept of Acoustic Black Hole (ABH) offers new impetus to tackle this problem. Most existing ABH structures are based on simple ABH cells. Apart from the reduced structural strength, systematic ABH effects occur typically above the cut-on frequency of the ABH element, which is perceived as a bottlenecking problem. To tackle the problem, this paper examines the sound radiation properties of a plate comprising periodically tangled ABH cells. Through combining ABH effects with sub-wavelength bandgaps (BGs), numerical and experimental studies show that the plate exhibits reduced sound radiation properties in an ultra-broad frequency range, far below the cut-on frequency of an ABH element. This is owing to the tangled nature of the ABH elements, which extends the actual dimension of the ABH, lowers its onset frequency and reduces the sound radiation efficiency through creating slow waves. Inside the BGs, the reduced sound radiation is mainly due to the redistribution of the vibration energy, basically confined to the excitation area. Capitalizing on the combined ABH and BG features alongside improved mechanical properties, the proposed structure shows promise as a light-weight solution for broadband noise reduction.

Acoustic Bruit Transduction Interface for Non-Invasive Vascular Access Monitoring.

Hemodialysis is a treatment for patients suffering from chronic or acute kidney disease, and is administered via an arteriovenous vascular access. One symptom of a dysfunctional vascular access are blood sounds (bruits) produced by turbulent flow. This paper discusses the design and characterization of a multichannel transducer array to capture blood sounds from multiple sites simultaneously. Recorded sounds can be classified by digital signal analysis to categorize severity of dysfunction based on acoustic features. Using a vascular access phantom with 5-80% degree of stenosis and blood mimicking fluid flowing at a rate of 850-1200 mL/min, we analyzed the acoustic properties of blood sounds recorded from a flexible microphone transducer. The signal bandwidth (2.25 kHz) and the dynamic range (60.2 dB) were determined, allowing optimization of a transimpedance transducer interface amplifier.Clinical Relevance-Vascular access stenosis causing turbulent flow produces bruits with spectral content related to degree of stenosis. A flexible microphone recording array could be used for point-of-care monitoring of vascular access function.

Research on Low Frequency Sound Insulation Properties of Membrane-Type Acoustic Metamaterials

To solve the problem of low-frequency noise control in ship cabins, a new membrane-type acoustic metamaterial (MAM) with bulges on the surface of thin films is designed based on the characteristics of lightweight and low-frequency sound insulation of membrane-type acoustic metamaterials. The sound structure coupling module of COMSOL multiphysical field coupling software is used to analyse the sound insulation performance of MAMs. The sound insulation properties of the additional mass film and self-similar fractal convex structure are further discussed. The metamaterial structure studied in this paper has a better sound insulation effect than ordinary film, which provides strong technical support for ship cabin noise control.

Experimental evaluation of pseudo-sound in a parametric array.

Parametric arrays have been widely investigated due to their high directivity in the low-frequency region when measuring the acoustic characteristics of materials, such as sound transmission and reflection properties, in the limited space of acoustic water tanks. Because a parametric array utilizes nonlinear interaction across the frequency components, nonlinear phenomena arise in both the acoustic medium and the hydrophone system. The unwanted nonlinear sound generated in the hydrophone and instrumentation is termed pseudo-sound. This study devised an experiment to measure the pseudo-sound without a truncator to assess the effect of the pseudo-sound in the near field. In order to separately measure the pseudo-sound, the hydrophone was placed close to the projector so that the pseudo-sound was dominantly generated. The method is based on the fact that, if we can suppress a parametric signal by minimizing the propagation path length in the medium, the resulting measured signal can be attributed to the pseudo-sound. The resultant signal levels were matched to the levels at corresponding distances based on the primary levels of a (separately conducted) distance-varying experiment. Finally, the suitability of the proposed technique was evaluated by comparing its results with the pseudo-sound levels measured using a truncator.

Densities, speeds of sound, refractive indices, excess and partial molar properties of polyethylene glycol 200 + benzyl methacrylate binary mixtures at temperatures from 293.15 to 318.15 K

Green and biodegradable solvents are requisite replacements to volatile organic solvents. Polyethylene glycols have been recognized as alternatives to volatile organic solvents in numerous industrial and pharmaceutical applications because of their unique properties. In this work the measurements of physicochemical properties, viz., densities, ρ, speeds of sound, u and refractive indices, nD of the binary mixtures of PEG 200 with benzyl methacrylate, including pure liquids, over the entire mole fraction range at the temperatures, T/K = 293.15 to 318.15 and at atmospheric pressure, p = 101 kPa. The experimental data were used to calculate the excess molar volume, VmE, excess isentropic compressibility, κsE, excess speed of sound, uE, excess acoustic impedance, ZE, excess molar isentropic compressibility, Ks,mE, excess refractive index, nDE and deviation in molar refraction, ΔRM . These excess properties were fitted with the Redlich-Kister polynomial equation. In addition, the partial molar volumes and partial molar compressibilities and excess partial molar volumes and excess partial molar compressibilities over the entire mole fraction range; and at infinite dilution were also calculated. The trends of these parameters with composition and temperature were discoursed from the point of view of intermolecular interactions existed in these mixtures.

The Role of Age and Exposure in English Vowel Perception and Production among Native Swahili Speakers

Vowel perceptual studies in Foreign Language Acquisition (FLA) settings where L1 is dominant are generally scarce. The aim of this study, therefore, is to explore the role of the age and exposure factors in the perception and production of English vowels [ɑ-ɜ; æ-ɑ; i-ɪ] by the native Swahili speakers whose exposure to the English language is through formal instruction in a predominantly FLA situation. The participants (n=40) were classified into two groups: Young learners and adult learners. Using Flege’s Speech Learning Model (SLM), we administered a vowel perception test, and a vowel production exercise. The results confirm that adult learners have an edge over younger learners whereby the former exhibited greater accuracy in determining vowel contrasts and production than the latter. Although both groups shared common difficulties in discriminating the vowel sounds, adult learners had recourse to their prolonged exposure and ingeniously used previously acquired knowledge and skills in sentence structure and meaning to aid discrimination in comparison to the younger learners. Finally, the study supports the SLM contention that adults retain capacities to acquire L1 to perceive the properties of L2 speech sounds and establish new phonetic categories.

Improvement of insulation properties of glass fiber fabric/epoxy composites modified by polymeric and inorganic fillers

AbstractGlass fiber fabric‐reinforced epoxy composites (GEC) have some weakness on both thermal insulation and sound absorption insulation, which are very important for many application areas such as aircraft, train, and so on. The main aim of this study is to improve both sound absorbent and thermal insulation properties of GEC by incorporating different fillers such as hollow glass microspheres (HGMs), polystyrene (PS) microfiber membrane, and PS solution. Results show that incorporation of PS solution into glass fiber fabric epoxy composite (GEC‐PS) provides higher sound absorption coefficient leading to an increase in the max SAC value from 0.1 to 0.4 and improvement in thermal insulation by decrease of thermal conductivity coefficient of GEC from 0.48 to 0.448 W/mK. Thermal insulation properties of GEC were improved by the use of PS microfiber membrane, which decreases the thermal conductivity coefficient of GEC from 0.48 to 0.438 W/mK. HGM did not improve both the thermal insulation and sound absorption insulation properties of GEC due to the agglomeration.

Sound insulation properties of membrane-type acoustic metamaterials with petal-like split rings

Membrane-type acoustic metamaterials (MAMs) are lightweight and flimsy materials with excellent low-frequency insulation performance, which breaks the limitations of the traditional mass law and provides a new idea for noise reduction in the low-frequency range. To further broaden the sound insulation bandwidth on the premise of lightweight design, a novel MAM with petal-like rings is proposed, and the parametric studies on the structural parameters of split rings are carried out in this paper. By combining the finite element model simulation and impedance tube test, the effectiveness of the proposed structure and the correctness of the numerical simulation are validated. Moreover, the sound transmission loss curves and modal shapes of four different structures are computed and analyzed to clarify the insulation mechanism of the novel structure. Finally, the width, the center angle, the centroid position, and the weight of the split rings in the novel structure are parametrically analyzed to figure out the regulation rules of the sound insulation characteristics.

Mechanical, sound and thermal properties of recycled expanded polystyrene concrete reinforced with 0.5% to 5.5% kenaf fibre

The incorporation of expanded polystyrene (EPS) in the concrete matrix has been increasingly popular in the construction industry in recent years, because of its excellent insulating and protective properties. However, there are shortcomings in the mechanical properties of the EPS concrete. This research aims to improve the tensile strength of the EPS with the usage of natural kenaf fibres, and the compressive strength with additives for example silica fume and naphthalene-based superplasticizers. The method of producing EPS–KF concrete mix is by selecting an EPS concrete mix with adequate strength by referencing local standard MS 76:1972 before determining the optimum percentage of kenaf fibres. This study found that with the optimum volume of EPS and kenaf fibres, the density of the concrete can achieve lightweight classification. In addition to that, the fibres are found to improve the tensile property, without compromising too much of the compressive property. The concrete produced from this study may be ideal for use as concrete bricks in the construction industry for non-structural purposes, especially in low-cost housing for its advantageous benefits and also to reduce the detrimental effects of waste to the environment.

Rethinking the phonetics of baby-talk: Differences across Canada and Vanuatu in the articulation of mothers' speech to infants.

Infant-directed speech (IDS) is phonetically distinct from adult-directed speech (ADS): It is typically considered to have special prosody-like higher pitch and slower speaking rates-as well as unique speech sound properties, for example, more breathy, hyperarticulated, and/or variable consonant and vowel articulation. These phonetic features are widely observed in the IDS of caregivers from urbanized contexts who speak a handful of very well-researched languages. Yet studies with more diverse socio-cultural and linguistic samples show that this "typical" IDS prosody is not consistently observed across cultures. We extended cross-cultural work by examining IDS speech segment articulation, which-like prosody-is also thought to be a characteristic phonetic feature of IDS that might aid speech and language development. Here we asked whether IDS vowels have different articulatory features compared to ADS vowels in two distinct linguistic and socio-cultural contexts: urban English-speaking Canadian mothers, and rural Lenakel- and Southwest Tanna-speaking ni-Vanuatu mothers (n=57, 20-46 years of age). Replicating prior work, Canadian mothers had more variable vowels in IDS compared to ADS, but also did not show clear register differences for breathiness or hyperarticulation. Vowels spoken by ni-Vanuatu mothers showed very distinct articulatory tendencies, using less variable (and less breathy) IDS vowels. Along with other work showing diversity in IDS phonetics across populations, this paper suggests that any understanding of how IDS might aid speech and language development are best examined through a culturally- and linguistically-specific lens.

High sound insulation property of prepared polypropylene/polyolefin elastomer blends by combining pressure-induced-flow processing and supercritical CO2 foaming

Light weight, high sound insulation property polymers have vast potential application in aviation, auto industry and the military application. Pressure induced flow (PIF) process form multi-layer-oriented structure in polymer matrix, and supercritical CO2 foaming (ScCO2) introduce gas into the matrix and increase the impedance mismatch between the phase, both of them enhance the polymer sound insulation property. In this paper, the sound insulation property of polypropylene (PP)/polyolefin elastomer (POE) blended composites prepared by the PIF process and the ScCO2 foaming were measured using the impedance tube. The sound insulation property is up to 103.56 dB in the frequency band of 1000–6000 Hz for 5 mm PIF PP/POE foam material, which it is 67.15 dB higher than PP/POE foam. By employing the multi-scale ffinite element analysis (FEA) modeling method, one two-phase FEA model of the monolith of 0.1 mm size and another 29 mm diameter bulk sample were developed based on SEM image of PIF PP/POE foamed materials at different scales. The monolith FEA model provided the effective material property for bulk sample. The finite element calculation results were consistent with the experimental result, verified the validity of the FEA modelling approach. The FEA simulation results reveal that the multi-layer-oriented structure of PIF material introduce the multi-layer impedance mismatch inside each monolith, and incident sound wave is reflected by those impedance mismatch, and this mechanism produce the high sound insulation property of PIF PP/POE foam materials.

Sound speed, submesoscale, and spice: The role of rapidly evolving instabilities in setting upper ocean properties

Sound speed characteristics in the upper ocean are sometimes thought to be set by a combination of mostly one-dimensional vertical mixing processes and (slow) mesoscale advection and stirring. However, a series of recent projects have showcased the role of small-scale (tens of meters to tens of km horizontally), rapidly evolving (hours to days) submesoscale instabilities in setting both stratification and sound speed properties. The observations also reveal that sound speed structure set by such processes is fundamentally three dimensional, with significant lateral gradients at a broad range of scales. Some relevant processes are frontogenetic and create sometimes rapid secondary circulations near lateral density gradients. Some are associated with wind-driven near-inertial oscillations or internal waves. Some of the more interesting recent observations concern the intersection of submesoscale and internal wave processes. Here, I will review a few highlights from the last decade of observations on unbalanced, nonlinear processes that conspire to set density, spice, and sound speed profiles in several contrasting oceans.

One problem, two solution approaches: Using the impedance translation theorem and equivalent circuits for graduate level homework

Research applications such as the study of musical instruments, human vocal tract effects on speech, automotive exhaust pipes, HVAC ducts, and others often utilize one-dimensional models of the acoustic systems to determine the resonance behavior and sound radiation properties. The impedance translation theorem and the equivalent circuits method both include all the physics associated with these one-dimensional systems, although one approach or the other may be more appropriate or straightforward to use depending on the result desired. Both these methods are taught at Brigham Young University in two graduate level courses. One of the most challenging and memorable homework assignments from each of these courses is based on using these techniques to analyze a particular acoustic system and compare its response with the real thing. This paper will overview these two techniques and outline how they are applied in homework assignments for these two courses to analyze phonemes produced by altering the human vocal tract.

Experimental measurement for assessing pseudo-sound effect in parametric array

The parametric array that generates narrow beams at low frequencies with apertures shorter than the wavelength and has been widely investigated when measuring the acoustic characteristics of materials, such as sound transmission and reflection properties. Because the parametric array utilizes nonlinear interaction across the frequency components, nonlinear phenomena arise in both the acoustic medium and the hydrophone. The unwanted nonlinear sound generated in the hydrophone and instrumentation is termed pseudo-sound. This work devised an experiment to measure the pseudo-sound for the purpose of isolating the “real” nonlinear difference frequency sound from the total nonlinear sound. Experimental results were validated by comparing its results with the pseudo-sound measured with a truncator (i.e., acoustic filter) to identify hydrophone nonlinearity.

The impact of tympanic membrane perforations on middle ear transfer function

PurposeInjury or inflammation of the middle ear often results in the persistent tympanic membrane (TM) perforations, leading to conductive hearing loss (HL). However, in some cases the magnitude of HL exceeds that attributable by the TM perforation alone. The aim of the study is to better understand the effects of location and size of TM perforations on the sound transmission properties of the middle ear.MethodsThe middle ear transfer functions (METF) of six human temporal bones (TB) were compared before and after perforating the TM at different locations (anterior or posterior lower quadrant) and to different degrees (1 mm, ¼ of the TM, ½ of the TM, and full ablation). The sound-induced velocity of the stapes footplate was measured using single-point laser-Doppler-vibrometry (LDV). The METF were correlated with a Finite Element (FE) model of the middle ear, in which similar alterations were simulated.ResultsThe measured and calculated METF showed frequency and perforation size dependent losses at all perforation locations. Starting at low frequencies, the loss expanded to higher frequencies with increased perforation size. In direct comparison, posterior TM perforations affected the transmission properties to a larger degree than anterior perforations. The asymmetry of the TM causes the malleus-incus complex to rotate and results in larger deflections in the posterior TM quadrants than in the anterior TM quadrants. Simulations in the FE model with a sealed cavity show that small perforations lead to a decrease in TM rigidity and thus to an increase in oscillation amplitude of the TM mainly above 1 kHz.ConclusionSize and location of TM perforations have a characteristic influence on the METF. The correlation of the experimental LDV measurements with an FE model contributes to a better understanding of the pathologic mechanisms of middle-ear diseases. If small perforations with significant HL are observed in daily clinical practice, additional middle ear pathologies should be considered. Further investigations on the loss of TM pretension due to perforations may be informative.

Language and Learner Specific Influences on the Emergence of Consonantal Place and Manner Features.

This article focuses on the emergence of consonantal place and manner feature categories in the speech of first language learners. Starting with an overview of current representational approaches to phonology, we take the position that only models that allow for the emergence of phonological categories at all levels of phonological representation (from sub-segmental properties of speech sounds all the way to word forms represented within the child’s lexicon) can account for the data. We begin with a cross-linguistic survey of the acquisition of rhotic consonants. We show that the types of substitutions affecting different rhotics cross-linguistically can be predicted from two main observations: the phonetic characteristics of these rhotics and the larger system of categories displayed by each language. We then turn to a peculiar pattern of labial substitution for coronal continuants in the speech of a German learner. Building on previous literature on the topic, we attribute the emergence of this pattern to distributional properties of the child’s developing lexicon. Together, these observations suggest that our understanding of phonological emergence must involve a consideration of multiple, potentially interacting levels of phonetic and phonological representation.

Cross-cultural adaptation and validation of the caregiver contribution to self-care of chronic illness inventory in China: a cross-sectional study

ObjectiveCaregiver contribution (CC) is important for the self-care behaviors of chronic disease individuals, as it could enhance patient outcomes. Therefore, it is necessary to assess this CC by using a...