Resonant Chamber Research Articles

The physiology of oral whistling: a combined radiographic and MRI analysis.

The fluid mechanics of whistling involve the instability of an air jet, resultant vortex rings, and the interaction of these rings with rigid boundaries (see http://www.canal-u.tv/video/cerimes/etude_radiocinematographique_d_un_siffleur_turc_de_kuskoy.13056 and Meyer J. Whistled Languages. Berlin, Germany: Springer, 2015, p. 74-774). Experimental models support the hypothesis that the sound in human whistling is generated by a Helmholtz resonator, suggesting that the oral cavity acts as a resonant chamber bounded by two orifices, posteriorly by raising the tongue to the hard palate, and anteriorly by pursed lips (Henrywood RH, Agarwal A. Phys Fluids 25: 107101, 2013). However, the detailed anatomical changes in the vocal tract and their relation to the frequencies generated have not been described in the literature. In this study, videofluoroscopic and simultaneous audio recordings were made of subjects whistling with the bilabial (i.e., "puckered lip") technique. One whistling subject was also recorded, using magnetic resonance imaging. As predicted by theory, the frequency of sound generated decreased as the size of the resonant cavity increased; this relationship was preserved throughout various whistling tasks and was consistent across subjects. Changes in the size of the resonant cavity were primarily modulated by tongue position rather than jaw opening and closing. Additionally, when high-frequency notes were produced, lateral chambers formed in the buccal space. These results provide the first dynamic anatomical evidence concerning the acoustic production of human whistling. NEW & NOTEWORTHY We establish a new and much firmer quantitative and physiological footing to current theoretical models on human whistling. We also document a novel lateral airflow mechanism used by both of our participants to produce high-frequency notes.

Measuring acoustic resonator properties using volume modification devices and numerical optimization

In this paper, a method for measuring resonator chamber volume and acoustic neck length by modifying chamber volume is presented. This method measures frequency changes caused by volume changes to determine core system volume and resonator neck length. Experimental measurements and data are presented along with measurement statistics. This method reduces the need for accurate resonator geometry knowledge by instead using external volume modification devices, where geometry is much easier to control.This method serves to enhance existing volume measurement methods such that sources of inaccuracy are minimized. Results indicate that resonator volume and acoustic neck diameter can be measured with reasonable accuracy (less than the 1% error associated with liquid-volume measurement techniques) when neck diameter and change in volume are known in advance.

Low-power noncontact photoacoustic microscope for bioimaging applications

An inexpensive noncontact photoacoustic (PA) imaging system using a low-power continuous wave laser and a kilohertz-range microphone has been developed. The system operates in both optical and PA imaging modes and is designed to be compatible with conventional optical microscopes. Aqueous coupling fluids are not required for the detection of the PA signals; air is used as the coupling medium. The main component of the PA system is a custom designed PA imaging sensor that consists of an air-filled sample chamber and a resonator chamber that isolates a standard kilohertz frequency microphone from the input laser. A sample to be examined is placed on the glass substrate inside the chamber. A laser focused to a small spot by a 40 × objective onto the substrate enables generation of PA signals from the sample. Raster scanning the laser over the sample with micrometer-sized steps enables high-resolution PA images to be generated. A lateral resolution of 1.37 ?? ? m was achieved in this proof of concept study, which can be further improved using a higher numerical aperture objective. The application of the system was investigated on a red blood cell, with a noise-equivalent detection sensitivity of 43,887 hemoglobin molecules ( 72.88 × 10 ? 21 ?? mol or 72.88 zeptomol). The minimum pressure detectable limit of the system was 19.1 ?? ? Pa . This inexpensive, compact noncontact PA sensor is easily integrated with existing commercial optical microscopes, enabling optical and PA imaging of the same sample. Applications include forensic measurements, blood coagulation tests, and monitoring the penetration of drugs into human membrane.

Could Fidicina mannifera (Hemiptera: Cicadoidea: Fidicinini) promote a resource pulse in two Brazilian Cerrado vegetation classes?

Cicadas are usually studied regarding their importance in agriculture. However, the possibility of this group to represent a pulse of nutrients can also imply on the success of a given species in the biome. The aim of this study was to assess the level of total soluble proteins and lipids of Fidicina mannifera (Fabricius, 1803), and to determine whether the species can promote a pulse of nutrients in two vegetation classes of the Brazilian Cerrado. To assess the pulse of nutrients, it was concluded the determination of total soluble proteins and lipids from samples of males and adult females of F. mannifera, and the spatial distribution of exuviae of this species was also calculated in two vegetation classes of the Brazilian Cerrado. The amount of protein provided by each individual did not differ between males and females (p = 0.66) but females had 40% more lipids than males (p = 0.05). Regarding F. mannifera the gallery forest offered 11.75 g/ha of protein, 3.91 g/ha of lipids, and the Cerrado stricto sensu offered 4.25 g/ha of protein, and 1.41 g/ha of lipid. The male cicadas have a hollow abdomen, which houses a resonance chamber for sound production in order to attract females to mate, and females store larger amounts of lipids, mainly located in the abdominal cavity, where the body fat is directly linked to the reproductive system for the development of the ovaries and egg production after emergence. The mass occurrence of F. mannifera in the Brazilian Cerrado and the fast availability of proteins and lipids make this species a food resource that can directly impact the diet of secondary consumers and scavengers, although the amount of nutrients available by F. mannifera does not promote a pulse of nutrients in the study site.

Microwave Imaging Using Normal Electric-Field Components Inside Metallic Resonant Chambers

A novel 3-D microwave imaging approach performed within a resonant air-filled metallic chamber is introduced and investigated. The new method utilizes the measurements of normal electric-field components at discrete points along the metallic chamber’s wall—near the chamber-wall boundary, the normal-field components are dominant, while the tangential components vanish. The inversion algorithm fully incorporates the resonant features of the low-loss chamber. A numerical study is used to quantify the imaging performance of using this technique compared with the traditional unbounded domain imaging. An experimental system is presented where the electric field is collected using 24 antennas distributed in three circumferential layers around an object of interest located inside the circular-cylindrical metallic chamber. For collecting the normal component of the field, two types of linearly polarized antennas are investigated: $\lambda /4$ monopole antennas and specially designed reconfigurable antennas (RAs), both projecting perpendicularly out from the chamber walls into the enclosure. The measured data are calibrated and then inverted using a multiplicatively regularized finite-element contrast source inversion algorithm. Using 3-D reconstructions of simple dielectric targets, it is shown that utilizing the RAs improves imaging performance due to a reduction in the modeling error introduced in the inversion algorithm.

Ambient horror: From sonic palimpsests to haptic sonority in the cinema of Kurosawa Kiyoshi

Abstract In ‘Ambient horror: From sonic palimpsests to haptic sonority in the cinema of Kurosawa Kiyoshi’, Steven T. Brown explores how sound flows modulate affective states and noncognitive responses to the ambient horror films of J-horror maestro Kurosawa Kiyoshi. This article considers elements such as the interrelations between noise and silence, the function of ambient drones and sonic palimpsests, and uses advanced spectral and surround field techniques to analyse sound design. Considering these elements, along with the status of the acousmatic voice, we gain a better understanding of how soundscapes contribute to the construction of horror as a space for what Brown calls ‘haptic sonority’. Haptic sonority is a liminal space that blurs the boundaries between the sonic and the tactile, and compels the audience to bear witness to the embodied effects of sound waves vibrating bodies as if they were resonance chambers. In horror cinema, such haptic sonority opens an intensive space where one does not so much hear sounds as one feels them in one’s body in ways that are by turns bone-rattling, gut-wrenching, and hair-raising. It is here that film touches our bodies and invites us to enter into composition with the micropolitics of sound as resonant subjects in a ‘cinema of sensations’.

Ultrasonic characterization of seagrass leaf blades (Posidonia oceanica)

It has been shown that simple mixture theory models are inadequate to describe low-frequency sound propagation through seagrass meadows and further understanding of the acoustic properties of seagrass tissue is necessary. To that end, we present two ultrasonic sound speed measurements on the Mediterranean seagrass Posidonia oceanica. First, a transit time measurement through a stack of 120 leaf blades at 2.25 MHz are compared to similar measurements made on macroalgae Ecklonia radiata. Sound speed differences are related to the gas content within the aerenchyma of seagrass and other tissue characteristics. Second, ultrasonic sound speed measurements through a suspension of finely divided P. oceanica leaf blades at frequencies between 1 and 4 MHz are compared to low-frequency (1-8 kHz) sound speed obtained on the same blade suspension by means of a resonance chamber.

Study on the principle of sound resonance in human whistling using physical models of a human vocal tract

The principle behind sound production in human whistling is relatively unknown. A good understanding of this principle would be beneficial to both trainer and trainee. Rayleigh identified whistling frequency as being determined by the mouth cavity and pointed out that earlier ideas that relate the sound-producing mechanism to the vibration of the lips are inaccurate. Wilson et al. reported that the human whistling resonant frequency is close to the Helmholtz resonant frequency, and through some physical-model-based experiments, they determined that the resonator can be excited by a flow through the smooth-edged orifices bounding the resonant cavity. Thus, the principles of whistling in terms of articulation have been reported to be based on the Helmholtz resonance. However, some whistlers can produce high-pitched sounds by blowing harder without changing the capacity of the resonance chamber, which is similar to a high-pitched sound produced by a wind instrument by air-column resonance. This work studies ...

Fluid-Solid Coupling and Experimental Realization of a Piezoelectric Atomizer under Standing-Wave Resonance

<abstract> <b> </b>This article introduces the design and analysis of a piezoelectric atomizer based on the principles of standing-wave resonance and a pressure-swirl nozzle. Experiments are conducted to demonstrate that the developed piezoelectric atomizer can produce uniformly sized liquid droplets. The atomizer uses piezoelectric composite plates to acquire a large displacement from the vibration of Pb(Zr, Ti)O₃ (PZT) ceramic and to exert excess pressure on the liquid using standing-wave resonance. The three-dimensional dynamic characteristics of the piezoelectric composite plates, considering the effect of the fluid-solid interface, are determined. An analysis of the fluid-solid coupling between the fluid in the resonance chamber and the vibration of the piezoelectric composite plates is conducted. The Sauter mean diameter (SMD) values of the ejected droplets and the flow rate of the piezoelectric atomizer are measured experimentally as different driving voltages. The experimental results demonstrate that the atomizer is capable of generating droplets with an SMD of 93.5 μm at a flow rate of 18.4 g/s. Relatively uniform droplets are formed below the ligaments, where the cone swirl sheet is fully developed. The piezoelectric atomizer has the potential for use in industrial and agricultural applications.

The Physiological Basis of Chinese Höömii Generation

The study aimed to investigate the physiological basis of vibration mode of sound source of a variety of Mongolian höömii forms of singing in China. The participant is a Mongolian höömii performing artist who was recommended by the Chinese Medical Association of Art. He used three types of höömii, namely vibration höömii, whistle höömii, and overtone höömii, which were compared with general comfortable pronunciation of /i:/ as control. Phonation was observed during /i:/. A laryngostroboscope (Storz) was used to determine vibration source-mucosal wave in the throat. For vibration höömii, bilateral ventricular folds approximated to the midline and made contact at the midline during pronunciation. Ventricular and vocal folds oscillated together as a single unit to form a composite vibration (double oscillator) sound source. For whistle höömii, ventricular folds approximated to the midline to cover part of vocal folds, but did not contact each other. It did not produce mucosal wave. The vocal folds produced mucosal wave to form a single vibration sound source. For overtone höömii, the anterior two-thirds of ventricular folds touched each other during pronunciation. The last one-third produced the mucosal wave. The vocal folds produced mucosal wave at the same time, which was a composite vibration (double oscillator) sound source mode. The Höömii form of singing, including mixed voices and multivoice, was related to the presence of dual vibration sound sources. Its high overtone form of singing (whistle höömii) was related to stenosis at the resonance chambers' initiation site (ventricular folds level).

Performance of a dual-process PVD/PS tungsten coating structure under deuterium ion irradiation

A dual-process coating structure was developed on a graphite substrate to improve the performance of the coating structure under anticipated operating condition of fusion devices. A thin multilayer W/Mo coating (6μm) was deposited by physical vapor deposition (PVD) method with a variation of Mo interlayer thickness on plasma spray (PS) W coating (160μm) of a graphite substrate panel. The dual-process PVD/PS W coatings then were exposed to 3.08×1024Dm−2 of 100eV D ions with a flux of 1.71×1021 Dm−2s−1 in an electron cyclotron resonance (ECR) chamber. After irradiation, surface morphology and D depth profiles of the dual-process coating were analyzed and compared to those of the simple PS W coating. Both changes in surface morphology and D retention were strongly dependent on the microstructure of surface coating. Meanwhile, the existence of Mo interlayer seemed to have no significant effect on the retention of deuterium.

Effects of Desliming and Hydroacoustic Cavitation Treatment on the Flotation of Ultrafine Bituminous Coal

ABSTRACTTesting was conducted to evaluate the effects of desliming in combination with hydroacoustic cavitation (HAC) treatment on flotation when processing nominal -150 μm Illinois-basin bituminous coal, which was obtained from a refuse stream at an operating coal-cleaning plant. Cavitation was produced either by flow through an ultrasonic resonator chamber or enhanced cavitation by initial flow through a cavitation chamber followed by flow through the ultrasonic unit. Desliming was carried out using a 102 mm diameter hydrocyclone. Flotation tests were conducted using a laboratory flotation cell for different reagent amounts and flotation times. The results indicated that desliming improved flotation substantially. Moreover, in some cases, HAC treatment provided an additional benefit by liberating ultrafine inorganic material prior to desliming.

Charlotte Delbo à l’écoute: Auditory Imagery in Auschwitz et après

Delbo is known for the mantra that defines her work: il faut donner a voir . Accordingly, scholarship has focused on the visual imagery in the three volumes that were eventually published as Auschwitz et apres . However, Delbo often demonstrates the limits to visually figurative language within the work itself. Her repeated expressions, “Essayez de regarder. Essayez pour voir,” become confrontations, rather than exhortations to the reader, who can never fully imagine the experience. This article examines the understudied role of auditory imagery in Delbo’s Auschwitz et apres and discusses the limits of visually figurative language in her work. I analyze two essential elements of Delbo’s auditory imagery: the mimetic perception demanded by the guttural cries in her prose as well as the delayed auditory sensory content produced in her poetic sections. The article concludes with a discussion of Jean-Luc Nancy’s concept of the self as a resonance chamber, which sheds light on the existential role of the auditory in Delbo’s testimonial strategy. Bearing witness to extreme suffering in Delbo’s work demands a careful mental listening to remedy insufficient mental looking .

Effect of colliding partners on the performance of SF6 and SO2 trace measurements in photoacoustic spectroscopy.

A photoacoustic (PA) cell was designed based on the numerical simulation and then was fabricated in order to investigate the effect of various buffer gases on the acoustic signals and the resonant frequencies. The sizes of resonator and buffer chambers were suitably selected to improve signal-to-noise ratio. Atmospheric SF6 impact is high due to its significant green house effect. A series of experiments were performed to detect SF6 trace in the air and various types of rare gases. Similar experiments were carried out for the urban and industrial pollutant SO2 in the same environments. The resonant frequencies were measured at various pressures for several rare gases, namely He, Ne, Ar, Kr, and Xe. The PA spectroscopy of molecular traces in various gases gives rise to sensible spectral shift. It was shown that the use of heavier buffer gases at atmospheric pressure lead to detection of the lower concentrations. In general, the relatively intense acoustic signal is recorded for the heaviest species Xe due to its large vibrational-transitional excitation cross section. Conversely, the light elements dissipate laser energy much larger than the heavy species during the successive collisional excitations. Therefore the trace molecules in helium exhibit a notable rise in the resonant frequency accompanying a small PA signal.

The problems of reducing the noise level on open sites of machine building plants and living areas

In this article there is an analysis of using noise-absorbing screens on the basis Helmholtz resonator to reduce the level of acoustic noise on open industrial sites of machinebuilding plants and adjacent living areas. A design realization of this screen was considered, the characteristic of which is a variable depth of the resonator chamber and the change of the clearance of the resonator throat. The evaluation of the efficiency of using the screen was performed using experimental modeling with an acoustic chamber and a screen model. It was shown that in the majority of the cases there is some attenuation of the acoustic signal in the zone in front of the screen. A conclusion was made about the possibility of reducing noise level in industrial and living zone

Effect of ultrasonic cavitation treatment on liberation and hydrocyclone separation of bituminous coal

Testing was conducted to evaluate the effects of hydroacoustic cavitation (HAC) treatment on two bituminous coal slurries and the subsequent separation of each slurry in a classifying hydrocvclone. HAC treatment was performed using a pilot-scale circuit fabricated by Fumess-Newb urge Inc. The circuit was designed to induce cavitation by means of flow through an ultrasonic resonator chamber or enhanced cavitation by initial flow through a cavitation chamber followed by flow through the ultrasonic chamber. The test materials were nominal −1,500-micron and −150-micron lllinois-basin bituminous coal slurries, which were obtained from an operating coal preparation facility. After 5 sec of HAC treatment, the median size of the −1,500-micron material was reduced, with ash values for certain size fractions decreasing more than 5 percent compared with untreated samples. Extending treatment time led to greater degradation of the +1,180-micron material and an increase in the −25-micron material, with ash reductions occurring for material in the −850+150-micron size range. Size degradation was less for the −150-micron material. Subsequent separation of the treated slurries was carried out in a hydrocvclone with diameter of 102 mm. HAC treatment led to a decrease in the ash value and an increase in the heating value of the underflow stream compared with the feed material. For example, the ash value was reduced by about 16 percent for the −1,500-micron material and 25 percent for the −150-micron material with heating value increases of 7 and 33 percent, respectively, after HAC treatment. Overall, HAC treatment appeared to have a slight effect on the size selectivity curves.

Black Soundscapes White Stages: The Meaning of Francophone Sound in the Black Atlantic

Black Soundscapes White Stages: The Meaning of Francophone Sound in the Black Atlantic

Compact multichannel spectrometer based on the array of two-component photonic crystal cavities

The model of the integrated on-chip spectrometer based on the two-component optical cavity is presented and studied numerically. Such a cavity consists, first, of a ridge photonic crystal waveguide, in which the structure period does not change. Second, the cavity contains a complementary material segment with an area of several photonic crystal periods. When combining the two components, a defect is formed. A resonant mode can be excited in it. Advantages of the proposed cavity model are considered. In particular, the ease of forming arrays of cavities and convenience of setting the resonant frequency by the introduction of optically nonlinear material directly into the cavity area, vertical electron pumping of the resonant chamber, or by the creation of dynamic nanophotonic elements.

Nanocrystal production in the presence of microwave radiation fields

A technology of production of nonmetal nanopowders and nanocrystals with characteristic dimensions of about 10 nm in the presence of microwave radiation fields is developed. Specially designed in the National Research Nuclear University (NRNU) MEPhI experimental microwave setup with a power of 5 kW and an operating frequency of 2450 MHz was used as a radiation source. Hydroxides/oxyhydroxides Zr — Y, Dy — Zr, and Dy — Hf placed in a special crucible located in a resonator chamber were used as parent materials.

Ancient Aztec drum, the Huehuetl

The Aztecs and other cultures in Mesoamerica used to build and play during their festivities and warriors gatherings, simple drums made out from a hollow tree trunk, carved in the inside in order to make a fairly uniform thick surface to form the resonant chamber, topped by an ocelot skin, and open in the bottom, usually by three supports made from the same tree piece, called huehuetl, which means that these drums were of different shapes and sizes, some of these trunks were highly decorated by carving in the surface three dimensional images related to animals, faces, warriors, and other figures. These drums were excited on the top either by bare hand or wood sticks, varying the sound by the strength of the hit, and the area of the ocelot skin actually hit. Here are presented some pictures of ancient huehuetls together with the acoustic analysis of the sounds produced with a small replica of this percussion instrument.