bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute Effects of Vibration Foam Rolling Warm-Up on Jump and Flexibility Asymmetry, Agility and Frequency Speed of Kick Test Performance in Taekwondo Athletes
Authors: Chen An-Hsu , Chiu Chih-Hui , Hsu Chin-Hsien , Wang I-Lin , Chou Kuei-Ming , Tsai Yung-Shen , Lin Yu-Fang , Chen Che-Hsiu
Published: September 2021

The effect of asymmetry on flexibility and jump in taekwondo athletes and the influence of vibration foam rolling on asymmetry and frequency speed of kick test has not been examined. This study examined the effects of three warm-up protocols on subsequent sports performance in elite male taekwondo athletes. Fifteen elite male taekwondo athletes (20.63 ± 1.18 years) completed three warm-up protocols in a randomized order: general warm-up [GW], GW with vibration foam rolling [GW + VR], and GW with double VR for the weaker leg [GW + double VR]), was delivered before the subsequent tests: flexibility, single-leg countermovement jump (CMJ), 505 agility, hexagon test, and multiple frequency speed of kick tests (FSKTs). Relative to GW, the GW + VR significantly improved the hexagon test (GW + VR = 11.60 ± 1.01 s; GW = 12.80 ± 1.58 s). In addition, the GW + VR and GW + double VR yielded greater kick numbers in FSKT 5 (GW + VR = 21.13 ± 1.96 reps; GW + double VR = 20.93 ± 1.67 reps; GW = 19.27 ± 1.62 reps) and a higher kick decrement index (GW + VR = 5.45 ± 2.57%; GW + double VR = 5.88 ± 3.22%; GW = 9.54 ± 5.00%). However, the GW + VR and GW + double VR did not significantly improve the flexibility and CMJ asymmetry performance. The GW + VR is more beneficial for warming up than the GW is among male collegiate taekwondo athletes.
EAS Arrays at High Altitudes Start the Era of UHE γ-ray Astronomy
Authors: Cao Zhen
Published: September 2021

The evolution of extensive air shower detection as a technique for γ-ray astronomical instrumentation for the last three decades is reviewed. The first discoveries of galactic PeVatrons by the Large High Altitude Air Shower Observatory demonstrate the importance of this technique in ultra-high energy γ-ray astronomy. Utilizing this technique, the origins of high energy cosmic rays may be discovered in the near future.
Imipramine Accelerates Nonalcoholic Fatty Liver Disease, Renal Impairment, Diabetic Retinopathy, Insulin Resistance, and Urinary Chromium Loss in Obese Mice
Authors: Chang Geng-Ruei , Hou Po-Hsun , Wang Chao-Min , Lin Jen-Wei , Lin Wei-Li , Lin Tzu-Chun , Liao Huei-Jyuan , Chan Chee-Hong , Wang Yu-Chen
Published: September 2021

Imipramine is a tricyclic antidepressant that has been approved for treating depression and anxiety in patients and animals and that has relatively mild side effects. However, the mechanisms of imipramine-associated disruption to metabolism and negative hepatic, renal, and retinal effects are not well defined. In this study, we evaluated C57BL6/J mice subjected to a high-fat diet (HFD) to study imipramine’s influences on obesity, fatty liver scores, glucose homeostasis, hepatic damage, distribution of chromium, and retinal/renal impairments. Obese mice receiving imipramine treatment had higher body, epididymal fat pad, and liver weights; higher serum triglyceride, aspartate and alanine aminotransferase, creatinine, blood urea nitrogen, renal antioxidant enzyme, and hepatic triglyceride levels; higher daily food efficiency; and higher expression levels of a marker of fatty acid regulation in the liver compared with the controls also fed an HFD. Furthermore, the obese mice that received imipramine treatment exhibited insulin resistance, worse glucose intolerance, decreased glucose transporter 4 expression and Akt phosphorylation levels, and increased chromium loss through urine. In addition, the treatment group exhibited considerably greater liver damage and higher fatty liver scores, paralleling the increases in patatin-like phospholipid domain containing protein 3 and the mRNA levels of sterol regulatory element-binding protein 1 and fatty acid-binding protein 4. Retinal injury worsened in imipramine-treated mice; decreases in retinal cell layer organization and retinal thickness and increases in nuclear factor κB and inducible nitric oxide synthase levels were observed. We conclude that administration of imipramine may result in the exacerbation of nonalcoholic fatty liver disease, diabetes, diabetic retinopathy, and kidney injury.
Improving hand hygiene measures in low-resourced intensive care units: experience at the Kigali University Teaching Hospital in Rwanda
Authors: Mvukiyehe Jean Paul , Tuyishime Eugene , Ndindwanimana Anne , Rickard Jennifer , Manzi Olivier , Madden Gregory R. , Durieux Marcel E. , Banguti Paulin R.
Published: September 2021

Background: Proper hand hygiene (HH) practices have been shown to reduce healthcare-acquired infections. Several potential challenges in low-income countries might limit the feasibility of effective HH, including preexisting knowledge gaps and staffing. Aim: We sought to evaluate the feasibility of the implementation of effective HH practice at a teaching hospital in Rwanda. Methods: We conducted a prospective quality improvement project in the intensive care unit (ICU) at the Kigali University Teaching Hospital. We collected data before and after an intervention focused on HH adherence as defined by the World Health Organization ‘5 Moments for Hand Hygiene’ and assuring availability of HH supplies. Pre-intervention data were collected throughout July 2019, and HH measures were implemented in August 2019. Post-implementation data were collected following a 3-month wash-in. Results: In total, 902 HH observations were performed to assess pre-intervention adherence and 903 observations post-intervention adherence. Overall, HH adherence increased from 25% (222 of 902 moments) before intervention to 75% (677 of 903 moments) after intervention (P < 0.001). Improvement was seen among all health professionals (nurses: 19–74%, residents: 23–74%, consultants: 29–76%). Conclusions: Effective HH measures are feasible in an ICU in a low-income country. Ensuring availability of supplies and training appears key to effective HH practices.
Acciones y alcances de la intervención del terapeuta ocupacional en niños con trastorno del espectro autista en escuelas regulares
Authors: Gateño-Galemiri Dalit , González-Murillo Aurora , Arce-Chavarría Eilyn
Published: September 2021

Introducción: El diagnóstico de Trastorno del Espectro Autista (TEA) crece progresivamente, reflejando un incremento de estudiantes con esta condición en escuelas regulares. Objetivo: determinar las acciones y alcances de la intervención del Terapeuta Ocupacional en niños con TEA que están en escuelas regulares. Metodología: referencias adquiridas en las plataformas EBSCOHOST, Google Académico, Dialnet. Palabras clave empleadas: TEA, Terapia Ocupacional, Escuela Regular. Utilizadas fuentes publicadas entre 2013 y 2019. Se incluyeron artículos anteriores al 2013. Fuentes redactadas en español e inglés. Se utilizaron 24 artículos científicos. Resultados: los principales obstáculos que enfrentan los niños con TEA en la educación regular son el desconocimiento sobre características del TEA, la falta del enfoque interdisciplinario y el desconocimiento sobre técnicas para intervenir dentro y fuera del aula. La intervención del Terapeuta Ocupacional en escuelas regulares se enfoca principalmente en abordar el procesamiento sensorial y las Actividades de Vida Diaria, capacitar a docentes para modular el comportamiento del estudiante, capacitar al equipo interdisciplinario y velar por la prevención y promoción de la salud de los estudiantes. Conclusiones: Los terapeutas ocupacionales son indispensables en la inclusión educativa para estudiantes con TEA. Algunos aspectos que lo demuestran es el trabajo multimodal, la estimulación sensorial y conductual y el trabajo con familiares. En Costa Rica falta exponer el perfil del terapeuta ocupacional y los beneficios que esta puede generar en estos estudiantes.
Research on the Layout Optimization of Acoustic Radiation Power Flow Reinforcement Based on Weight-Guide method
Authors: Teng Xiaoyan , Li Qiang , Jiang Xudong , Yan Zhihua
Published: September 2021

In order to reduce the noise radiation of the plate and shell structure, the Weight-Guide method is used to optimize the layout of stiffeners for acoustic radiation power flow. Firstly, Rayleigh integral method and Helmholtz equation are used to derive the acoustic radiation power flow,
and the sensitivity is calculated by using explicit approximation technique, which takes the acoustic power flow as the objective function. Secondly, the guide weight method is used to update the design variables to optimize the layout of stiffeners and change the shape of the vibration structure,
so as to transform the structure into a weak radiator to reduce the radiated sound power. Finally, the optimized structure can optimize the frequency of the partial frequency band reduction by the analysis of numerical examples, and at the same time, the full band optimization of the sound
power spectrum can be achieved by changing the number and position of the peaks.
Impact sound pressure values - Field measurements for different configurations of concrete slabs on the ground
Authors: Larsen Bernt Mikal
Published: September 2021

The presentation will summarize and discuss values of field measured normalized impact sound pressure level L'n,w measured sideways with different configurations of concrete slabs on ground within buildings. All results are adjusted to receiving room volume of 100 m3 and with thickness
of concrete slab 80-100 mm. Measurement on continuous concrete slab on expanded polystyrene gives L'n,w between adjoining rooms of 74 dB. Different principles of splitting have been investigated to evaluate the effect on L'n,w. The configuration where only the concrete slab is split (and with
a plastic film between the concrete base and the upper layer of expanded polystyrene), gives L'n,w of approximately 66 dB which is 8 dB lower than for a continuous bare concrete slab. When both the concrete slab and the upper layer of expanded polystyrene are split, measurements show L'n,w
of 58-61 dB for the case of no flooring, which is 13-16 dB lower than for a continuous concrete slab (no split). When both concrete slab and all layers of polystyrene are split down to continuous foundation measurements show L'n,w of 55 dB. The situation with concrete slab and all layers of
polystyrene split and with no foundation beneath gives L'n,w of 46 dB. Consequences for airborne sound and R'w will be discussed as well for the above mentioned configurations.
Analysis of the acoustical environment of classrooms in three brazilian public schools through measurements and 3d simulation
Authors: Horst Andrade Fernanda , Scoczynski Ribeiro Rodrigo , Teixeira Braz César Manuel
Published: September 2021

The present study analyses the outdoor and indoor sound pressure levels (SPL) and the reverberation time (RT) measured in three Brazilian public classrooms. For the SPL, a sound level analyzer (class II) was used, and for the RT it was used a smartphone for the measurements. The sound
sources were the impulses of bursting balloons and the data was processed in a MatLab toolbox (ITA-Toolbox). The classrooms were also simulated in an open source modeling software (I-SIMPA), using ray-tracing principles. Based on the results of the simulations, supported by the low-cost measurements,
it was observed that the classroom didn't reach the national standards for classroom acoustics. Some improvements were designed with sustainable materials in order to reach the lower limits of the standards using the same room acoustics software. It was observed that the low-cost measurements
helped on the diagnosis of classroom's acoustic issues which was also verified in the 3D simulation. This procedure showed itself as a cheap solution for classroom acoustic designs.
Broadband force spectrum of a pump-jet under inflow turbulence
Authors: Shi Shuaikang , Xiuchang Huang , zhiqiang Rao , hongxing Hua
Published: September 2021

To clarify the characteristics of unsteady force spectrum of a pump-jet running under inflow turbulent,the turbulence grid and Fourier synthesis method is employed to produce incoming turbulence with spatial flow structure and temporal fluctuation, which is combined with LES (large
eddy simulation) to obtain broadband unsteady force spectrum of the pump-jet. The results show that the proposed method could obtain the unsteady force broadband spectrum for duct, stator and rotor. The unsteady force broadband spectrum of the pump-jet is composed of the "hump" around
the blade passing frequency and its multiples, the characteristic line spectrum at the stator blade passing frequency and shaft frequency of adjacent stator multiples. With the number of blades increasing, the "hump" becomes more obvious, the characteristic peak changes periodically
and reaches the minimum when the number of blades is the number of rotors. Due to the use of the stator and duct, the amplitude of the unsteady force broadband spectrum of the pump-jet is higher than propeller, but the "hump" is not as obvious as propeller. The research is helpful
to clarify the unsteady force characteristics of pump-jet induced by turbulence, and provide ideas for the vibration and noise reduction of pump-jet.
Turbulent model validations with CFD/wind tunnel test and application to SEA for wind noise prediction
Authors: Aizawa Kai , Terakado Susumu , Komada Masashi , Morita Hidenori , DeJong Richard , Sorenson Steve
Published: September 2021

Wind noise is becoming to have a higher priority in automotive industry. Several past studies investigated whether SEA can be utilized to predict wind noise by applying a turbulent spectrum model as the input. However, there are many kinds of turbulent models developed and the appropriate
model for input to SEA is still unclear. Due to this, this paper focuses on clarifying an appropriate turbulent model for SEA simulation. First, the input turbulent pressure spectrum from five models are validated with wind tunnel tests and CFD. Next, a conventional numerical approach is used
to validate models from the aspect of response accuracy. Finally, turbulent models are applied to an SEA model developed for a wind tunnel, and the SEA response is validated with test data. From those input/response validations, an appropriate turbulent model is investigated.
Enhanced modal matching method for perforated and micro-perforated partitions
Authors: Maury Cédric , Bravo Teresa
Published: September 2021

Perforated multilayer partitions are widely used in many problems for the aerospace and automotive industries and air-conditioning systems. Combinations of macro and micro-perforated perforations across the constitutive partition layers can provide different physical mechanisms for
diverse control strategies depending on the problem requirements. However, there is a lack of unified numerical or analytical description able to provide accurate results over a broad frequency range for a wide range of diameter perforations ranging from supra-millimetric to sub-millimetric
apertures. Furthermore, most of them do not account for the beneficial effects on the partition dissipation of the in-hole non-planar modes, albeit evanescent. In this work, an enhanced modal matching (EMM) method is presented that accounts for in-hole high-order modes as well as visco-thermal
boundary layer effects inside the holes and over the outer surfaces surrounding the holes. The analytical results have been compared against effective models, numerical models and impedance tube measurements. They show good agreement for single and multi-layer partitions within the corresponding
bandwidths of validity. Parametric studies have concluded that the panel thickness-to-hole diameter ratio is a key factor that plays a crucial role on the prominence of the in-hole radial modes and outer visco-thermal effects in the dissipation properties.
Diffuse sound absorption modelling of complex finite absorbers using a hybrid deterministic-statistical energy analysis approach
Authors: Van hoorickx Cédric , Didier Paul , Reynders Edwin
Published: September 2021

This contribution presents a numerical approach to quantify the response of an absorber in a diffuse reverberation room. Conventionally, this is done by considering an infinite absorber coupled to an acoustic halfspace. It is, however, well known that the diffuse absorption coefficient
for a finite absorber can be quite different due to what is referred to in literature as the edge effect. A finite size correction has been developed previously, but it is only applicable to homogeneous absorbers and is based on a computationally costly quintuple integration. This contribution
presents an alternative approach in which a deterministic model, e.g. using the finite element or modal transfer matrix method, is coupled with a statistical model of the room using a hybrid deterministic-statistical energy analysis framework. With this framework, also the theoretical uncertainty
on this diffuse sound absorption that is inherent in the diffuse field assumption can be quantified, i.e. the variance of sound absorption results that can be theoretically expected across an ensemble of reverberation rooms of the same volume. The methodology is numerically and experimentally
validated for several absorber types.
How to make sell and buy quiet a reality in Britain
Authors: Wu Tao , Brereton Paul , Patel Jacqueline
Published: September 2021

Hearing loss caused by excessive exposure to noise at work remains reportedly widespread. Purchase of quieter machinery is an efficient method of reducing both occupational noise exposure and the need to manage risk from noise, but it requires reliable noise information. Machinery supplied
in Britain must have noise risk minimized and, where noise continues to present a risk, be supplied with data making clear the potential for noise risk, enabling identification of lower noise models and indicating methods of controlling that risk. In 2012 a pre-market surveillance exercise
reported 80% non-compliance with these legal requirements and found it highly unlikely that buyers and users of machinery could make reliable decisions based on the noise data provided with machines. This paper considers the prospect of Sell and Buy Quiet becoming a reality in Britain through:
restoring stakeholder confidence in noise data; establishing incentives for stakeholder action; making low noise machinery identifiable; clarifying and simplifying noise legislation; and improving some noise test codes.
Acoustic space filling curve metamaterials for grazing flow in Jet engine inlets
Authors: Glover Jennifer , O'Boy Dan
Published: September 2021

Acoustic metamaterials research has grown exponentially in the past 10 years driven by the advances in manufacturing and an increased understanding of damaging environment noise. 2020 was the first noise reduction target as set by Advisory Council for Aircraft Research and Innovation
in Europe with a relative 50% decrease. This was missed by current Jet engine noise control technology; however, metamaterials offer an encouraging alternative. Space Filling Curves (SFC) have the potential to provide a lightweight, thin, high performance acoustic liner. SFC have a history
in mathematical geometry dating back to the 1890's but are a comparatively new addition to acoustics. They are designed with a sub-wavelength curled cross-section creating a maze-like pattern which slows acoustic wave propagation through the liner enabling characteristics such as negative
refraction and low frequency attenuation. This paper contains a comparison of some of the most promising SFC metamaterial acoustic liner designs, in terms of the fundamental theory of the design category and a discussion of the reflection, absorption and transmission characteristics in terms
of a grazing flow conditions. Computer simulation and impedance tube based experimental testing compares the designs. The paper concludes with future application for aeroacoustics with particular focus on the engine inlet.
Influence of the acoustic structures placement on the measurements in a reverberation room
Authors: Wang Yueyue , Li Xianhui , Zhao Junjuan , Li Xingyun , Zhu Liying , Wang Wenjiang
Published: September 2021

Absorption coefficient is a signification index of acoustic structures, which is useful to determine acoustic treatment with a good sound-absorbing characteristic. To make the sound absorption of acoustic structures measured in a reverberation room more closely approximates the sound
absorption that would be performed under the applicational condition, this paper studies the influence of different placements on the measurements in the reverberation room. In this paper, the absorption coefficients of micro-perforated membrane and micro-perforated stretch ceiling space sound
absorbers are measured, which are placing in the middle of the reverberation room, close to the side walls of the reverberation room and in the corner of the reverberation room respectively. The experiments show that different placements of acoustic material in reverberation room have obvious
effect on sound absorption above the 500Hz. It is more efficient to place materials in the middle of the reverberation room, while the absorption of being close to the side walls or in the corner of the reverberation room weakens. The results were agreed with the measurement of micro-perforated
stretch ceiling space sound absorbers. It is useful to optimize the arrangement of acoustic materials and structures in controlling the building and rooms noise.
Aeroacoustic simulation of a cross-flow fan using lattice Boltzmann method with a RANS model
Authors: Kusano Kazuya , Furukawa Masato , Sakoda Kenichi , Fukui Tomoya
Published: September 2021

The present study developed an unsteady RANS approach based on the lattice Boltzmann method (LBM), which can perform direct aeroacoustic simulations of low-speed fans at lower computational cost compared with the conventional LBM-LES approach. In this method, the k-ω turbulence
model is incorporated into the LBM flow solver, where the transport equations of k and ω are also computed by the lattice Boltzmann method, similar to the Navier-Stokes equations. In addition, moving boundaries such as fan rotors are considered by a direct-forcing immersed boundary method.
This numerical method was validated in a two-dimensional simulation of a cross-flow fan. As a result, the simulation was able to capture an eccentric vortex structure in the rotor, and the pressure rise by the work of the rotor can be reproduced. Also, the peak sound of the blade passing frequency
can be successfully predicted by the present method. Furthermore, the simulation results showed that the peak sound is generated by the interaction between the rotor blade and the flow around the tongue part of the casing.
Route survey research of US military aircraft at Futenma Air Base and Kadena Air Base in Okinawa Prefecture
Authors: Tokashiki Takeshi
Published: September 2021

Currently, about 186.09 km2 of US military bases are located in Okinawa Prefecture, accounting for about 10.4% of the prefecture's land area, and about 70% of US military bases nationwide are concentrated. Many of the US military bases are located in or near urban areas, and have an
impact on the city planning of related municipalities. Among them, the aircraft noise problem is serious, and noise exceeding 100 dB (value observed in the residential area at the measurement point) such as takeoff and landing noise and engine adjustment noise is generated on a daily basis,
which greatly deteriorates the living environment of the local residents. It is a factor. In response to this, the national government has taken measures such as soundproofing work. In this study, the subjects were Kadena Air Base and Futenma Air Base, and continuous measurements were made
around the bases to investigate the surrounding sound environment.
Phase calibration method for microphone array based on multiple sound sources
Authors: Jiang Bo , Liu XiaoQin , Wu Xing
Published: September 2021

In the microphone array, the phase error of each microphone causes a deviation in sound source localization. At present, there is a lack of effective methods for phase error calibration of the entire microphone array. In order to solve this problem, a phase mismatch calculation method
based on multiple sound sources is proposed. This method requires collecting data from multiple sound sources in turn, and constructing a nonlinear equation setthrough the signal delay and the geometric relationship between the microphones and the sound source positions. The phase mismatch
of each microphone can be solved from the nonlinear equation set. Taking the single frequency signal as an example, the feasibility of the method is verified by experiments in a semi-anechoic chamber. The phase mismatches are compared with the calibration results of exchanging microphone.
The difference of the phase error values measured by the two methods is small. The experiment also shows that the accuracy of sound source localization by beamforming is improved. The method is efficient for phase error calibration of arrays with a large number of microphones.
Review of acoustically related design factors for three recent Los Angeles area music studios.
Authors: Brown Michael
Published: September 2021

The design of a professional-quality music recording studios involves a specific set of challenges, namely the need to provide high levels of sound isolation, rigorous noise and vibration control for building support systems, and the provision of acoustically appropriate room finishes.
The optimization of design solutions for each of these challenges depends upon project-specific requirements, including aesthetic objectives, base building constraints and the musical genres being recorded. This paper reviews how these challenges were successfully addressed in three recent
Los Angeles area music recording/broadcast studio projects. Projects reviewed include a recording studio at University of California, Los Angeles, where challenges included the need to accommodate all musical genres, from jazz, to orchestra, to drum ensembles. The two other studios were both
for broadcast organizations: KCRW, an influential NPR-affiliated music-orientated radio station and for the commercial radio broadcaster SiriusXM. The paper includes discussion of why and how various acoustical techniques were utilized, including use of "floating" construction and
live room variable acoustics. Solutions for successfully incorporating significant areas of glazing into live rooms and accommodation of audiences are also discussed, along with the various acoustical room finishes that were applied.
Soundscape composition analysis combined with acoustics and musicology: a case study on the music piece of Daybreaking
Authors: Ju Zhanjie , Deng Zhiyong , Xue Xushan , Liu Aili
Published: September 2021

With its own unique musical vocabulary oundscape composition has been unprecedently developed all over the world. The analysis of music s from the perspective of acoustics has its own advantages that cannot be replaced by the traditional musicology. Based on music named Dayb for a hope
to overcome COVID-19, this paper analyzes the acoustic elements of , frequency spectrum and waveform. Combined with the traditional musicology, it can show that the undulation of waveform has associated with the formal structure and the visualization of music. The frequency spectrum shows
that as the climax of the piece, the sound has a high energy in the range of 300-1000Hz, which is one of the extremely sensitive frequency ranges for human. The composer not only skillfully integrates the chanting of monks with the complex environmental sounds, but also reflects the innovative
composition skills. The change of from weak to strong or contrarily is also in line with the emotional expression, that is, the core idea of moving from nature to nature. Since soundscape c retains more information, it is easier to immerse the audience in the listening process and appreciate
the beautiful hope rather than the difficulty of understanding it.
An isogeometric formulation of locally-conformal perfectly matched layer for acoustic scattering problems
Authors: Mi Yongzhen , Yu Xiang
Published: September 2021

This paper presents an isogeometric formulation of the locally-conformal perfectly matched layer (PML) for time-harmonic acoustic scattering problems. The new formulation is a generalization of the conventional locally-conformal PML, in which the NURBS patch supporting the PML domain
is transformed from real space to complex space. This is achieved by complex coordinate stretching, based on a stretching vector field indicating the directions in which incident sound waves are absorbed. The performance of the isogeometric PML formulation is discussed through several acoustic
scattering problems, spanning from one to three dimensions. It is found that the proposed method presents superior computational accuracy, high geometric adaptivity, and good robustness against challenging geometric features. The geometry-preserving ability inherent in the isogeometric framework
could bring extra benefits by eliminating geometric errors that are unavoidable in the conventional PML. Meanwhile, these properties are not sensitive to the location of the sound source or the depth of the PML domain.
Loudspeaker-based sound reproduction for evaluating noise transmission into the car cabin
Authors: Kuntz Matthieu , Müller Gregor-Johannes , Kalinke Peter , Seeber Bernhard U.
Published: September 2021

Virtual and laboratory-based design techniques can accelerate the development process over conventional prototype-and-field-test procedures. In car acoustics, the transmission of outside airborne noise into the cabin needs to be understood and managed. Here, we evaluate the accuracy
of sound field recording and reproduction techniques for investigating the transmission of airborne noise into the driver's cabin of a car. Reference measurements of a real sound field, generated by a truck with idling engine to create a realistic scenario, were carried out in a semi-anechoic
chamber. The reference sound field was recorded inside and around a test car. Additionally, a spatial recording of the reference sound field was carried out and used to reproduce the reference sound field over a loudspeaker array in a different, fully anechoic chamber, where the sound field
was again measured inside and around the same test car. A comparison of the measured loudness inside the test car shows that this key parameter for sound quality could be reproduced rather faithfully over a loudspeaker array in a controlled testing facility.
Round-robin testing on Sound power level measurement for Reference Sound Source and Office printer
Authors: Shimoda Kohei
Published: September 2021

Round-robin testing for two samples, Reference Sound Source in accordance with ISO 6926 and Office printer with electrophotographic engine, were executed by seven testing laboratories in Japan on 2020. All tests were executed with parallelepiped measurement surface in hemi anechoic
chamber in accordance with testing standard for engineering-grade sound power determination, ISO 3744:2010. The results show that sample standard deviation for RSS is better than printer. Standard deviations for overall A-weighted sound power level for two samples are better than combined
standard uncertainties calculated with reference example of standard deviations in ISO 3744 (1.5 dB for Reference Sound Source as standard deviation of operating/mounting condition is negligibly small, 1.6 dB for printer as stable operating/mounting condition 0.5 dB). This paper also indicates
tips for those who would conduct round-robin testing to obtain valid results by obviating incorrect operations and malfunctions of printers or similar equipment from the experience of some round-robin tests.
3D shape optimization of loudspeakers
Authors: Andersen Peter Risby , Cutanda Henríquez Vicente , Aage Niels , Kook Junghwan
Published: September 2021

Improving the performance of loudspeaker units and cabinet designs traditionally relies on a combination of trial and error, sometimes based on a lumped parameter modelling approach. During the last decades, however, large-scale numerical simulations are playing a growing role as a
means of improving performance of complex engineering devices such as loudspeakers. However, a numerical model still relies on the experience of the operating engineer to make the appropriate design changes. This can be a difficult task. The use of numerical simulations combined with optimization
has a huge potential for further guiding the design process of advanced industrial products where intuition alone is not sufficient. Nevertheless, broadband acoustic simulations are still very time consuming. In this work, we explore the efficiency of a newly proposed semi-analytical adjoint
sensitivity approach based on the boundary element method in combination with a lumped parameter model. The sensitivity analysis is used to shape optimize the cabinet of a loudspeaker using free form deformation. The objective of the optimization is to improve frequency responses and directivity
patterns.
Enhancing Noise Management Strategy: Recommendations from the strategy literature.
Authors: Heyes Graeme
Published: September 2021

Airports are required to manage noise impact owing to their requirement to obtain a social license to operate, and to comply with legislation such as the ICAO Balanced Approach and Environmental Noise Directive. Research has however shown that noise management actions and interventions
often take a techno-centric approach, are implemented in silos, and that their success beyond noise metrics is rarely evaluated. Moreover, the success of Noise Action Plans in driving long-term noise management outcomes has also been critiqued at a number of levels. In the context of this
background, this paper outlines the case for more strategic approaches to noise management and, drawing on the academic strategic literature, outlines approaches to developing such strategies that can be followed by airports. The aim of such approaches is to complement existing noise management
guidance by providing step-processes that can aid airports in developing robust, repeatable, evaluable, and successful noise management strategies that are consistent with wider airport strategy and that are sympathetic to the needs of airport residents.
Priorities for occupational noise in Britain
Authors: Steel Chris , Brereton Paul
Published: September 2021

Regulation of occupational exposure to noise in Britain for 50 years has reduced risk. However, statistics from around the globe (and in Britain alone) suggest that the range in harm is between around zero and more than 1 in 4 workers exposed to high noise. The uncertainty in statistics
and the potential high incidence and prevalence of harm justifies investigation. In Britain, we will investigate the current risk of occupational hearing loss and the effectiveness of current noise control measures. We propose to gather data during inspections of industries that are known
to have high levels of workplace noise. Finding high incidence of hearing damage will indicate a failure of immediate management of risk and likely result in enforcement action. We propose to review employers' control of noise propagation in the workplace through use and maintenance of noise
controls supplied with machines and supplemented with acoustic barriers and noise havens. We propose to review suppliers design and build of noise control into their products and their reported noise emissions for noisiest typical use. We are looking to benefit from the experience of our global
counterparts before finalising our plans.
Multi-channel feedforward active noise control system for reducing snore noise with snore noise-term detection
Authors: Nakamura Koki , Iwai Kenta , Nishiura Takanobu
Published: September 2021

In this paper, a multi-channel feedforward active noise control system for reducing snore noise with noise-term detection is proposed. The snore noise consists of a noise-term and a silent-term, and it is difficult to reduce the snore noise by the active noise control system. Since
the conventional multi-channel feedforward active noise control system updates the noise control filters even in the silent-term, the conventional active noise control system updates the noise control filters unnecessarily. Therefore, the proposed multi-channel feedforward active noise control
system introduces threshold processing to update the noise control filters only in the noise-term. Owing to this process, it is possible to reduce the update count of the noise control filters. Simulation results show that the proposed active noise control system can reduce the snore noise
as same as the conventional active noise control system and can reduce the update count of the noise control filters compared to the conventional active noise control system.
A method to predict the flow-induced noise of an open cavity of a complex geometry
Authors: Zhong Tingsheng , Yang Cheng
Published: September 2021

Shear flow past a cavity involves a complex fluid dynamic process. Of vital importance is the occurrence of self-sustained oscillations that give rise to tones and the amplitudes of which may be further amplified if the hydrodynamic mode is coupled with the cavity mode. Extensive efforts
have been made to investigate the mechanisms of such a simple yet compelling system as well as to predict the noise generated, while most of them are focused on geometry of rectangular shape. For an irregular shaped cavity, numerical methods are usually used which are computationally expensive.
A method is developed to predict the tones generated by the shear flow past an open cavity of a complex geometry. In view of the feedback process involved within the system, a describing-function method decomposing the system into a non-linear part and a linear part is used. The linear description
function is established by the patch mobility method where the transfer function between patches is extracted from finite element results, while the nonlinear description function is established based on the vortex sound theory. The proposed method showed a superb computation efficiency over
CFD method and its accuracy was justified by comparing with the results of public literature.
Vibration level induced by the friction of two rough surfaces weakly loaded
Authors: Assemien Modeste , Le Bot Alain
Published: September 2021

This paper presents an experiment to measure the vibration level generated when a light solid slides over a dry and rough surface. The experimental set-up is based on linear constant motion with speed range from 1 to 1000 mm/sec. The aim is to study the evolution of the vibration level
as a function of the sliding speed and the friction area. Measurements show that the vibration level is a logarithmic increasing function of the sliding speed with a transient velocity. It is also observed that two regimes exist for the evolution of vibration level versus apparent contact
area. On the one hand the vibration level is proportional to the friction area, but on the other hand this level is constant.
A semi-analytical method for the vibration of cylindrical shells with embedded acoustic black holes
Authors: Deng Jie , Guasch Oriol , Maxit Laurent , Zheng Ling
Published: September 2021

Embedding acoustic black holes (ABHs) on beams and plates has revealed as an appealing passive method for noise and vibration reduction. However, most ABH designs to date only concern straight beams and flat plates, while cylindrical structures are commonly found in the aeronautical
and naval sectors. In this work, we suggest a semi-analytical method to compute the vibration field of a cylinder with an ABH indentation. We also show the ABH efficiency in terms of shell vibration reduction. It is proposed to resort to Gaussian basis functions in the framework of the Rayleigh-Ritz
method, to reproduce the ABH cylinder vibration field. The ABH shell displacements in the three directions are decomposed in terms of Gaussian functions, which can be dilated and translated analogously to what is done with wavelet transforms. The functions are also forced to satisfy the continuity
periodic conditions in the shell circumferential direction. The Gaussian expansion method (GEM) results in high precision at a low computational cost. The suggested semi-analytical method is validated against a detailed finite element (FEM) model. Modal frequencies and modal shapes are recovered
very accurately. Besides, the mean square velocity of the annular ABH shell under point external excitation is compared to that of a uniform shell, in the 50-1000 Hz frequency range. Noticeable vibration reduction is achieved.
Optimal ANC System Arrangement Based on Complete System Analyses Applying COSMOL Multiphysics and Matlab
Authors: Wang Miqing , Wen Shulin , Gan Woon-Seng
Published: September 2021

In real active noise control system implementation, the arrangement of secondary sources and error microphones have significant effect on the performance of the system. Analytical and experimental ways are usually combined to determine the best system layout. In this paper, we use COSMOL
Multiphysics to accurately model the acoustic environment in enclosures with the real measured dimensions and parameters. Matlab is adopted to simulate the basic active noise control algorithms. The combined simulation results are used to decide the optimal system layout of the real ANC system.
Experiments are conducted on a real ANC system with EVAL-21489-EZLITE from ADI to validate the analyzed and simulation results.
Countermeasures against floor impact sound by heavy impact source of a box floor structure in a reinforced concrete wall construction testing device
Authors: Tomita Ryuta , Abe Kyoko
Published: September 2021

We have performed experimental examinations for the purpose of proposing a floor finishing structure with superior effects in terms of combating heavy-weight floor impact sound. We have developed a box floor with ease of construction and excellent heavy-weight floor impact sound insulation
performance and examined its effect with a 1200 × 1200 mm test piece connected to inter-noise 2020. The box floor has a floor finishing structure with anti-vibration and sound insulation measures aimed at improving measures against heavy-weight floor impact sound. We herein report the
results of a basic examination on the reduction of the transmitted heavy-weight floor impact sound of a box floor structure in a reinforced concrete wall construction testing device when the area is further expanded to about 10 . As a result, with the air layer under the box floor open, the
floor impact sound level was reduced by 9 dB in the 63-Hz band compared to the bare surface. In addition, with the air layer at the bottom of the BOX floor sealed, the floor impact sound level was reduced by 5 dB in the 63-Hz band compared to the bare surface.
Acoustical Conformance with FGI for Tenant Improvements in Outpatient, Medical Office or Clinic Facility Sound Isolation/Privacy Design
Authors: Evans Jack B , Logsdon Edward
Published: September 2021

Acoustical privacy and noise control design and implementation guidance is needed, regarding Facility Guidelines Institute (FGI) criteria for outpatient medical facilty tenant improvements (TI). TI in existing commercial buildings or medical office buildings may not have capital budgets
or expected facility/lease life that hospitals enjoy. Full conformance to FGI criteria and guidelines may be limited; by economic feasibility and by constructability. Design professionals can use "good practice" space planning, demising assembly selection, and electronic sound masking
to achieve appropriate acoustical privacy within reasonable capital expense budgets. Consider FGI criteria for demising partition, ceiling, door and window selections plus infrastructure equipment and material selections that can provide cost-effective lightweight, common construction standards.
The objectives are to protect the privacy of patient information and provide quiet spaces, free of transient disturbance for clear speech communications. Continuous ambient sound increases speech privacy including speech transmitted from enclosed quiet spaces. Criteria for acoustics, speech
privacy,continuous noise and masking exists in FGI. Temporal level changes (on/off, transients) and tonality (spectrum smoothness or balance) should be considered in basis-of-design (BoD). This paper will present design guidelines for selecting demising assemblies and supplemental sound masking
for outpatient clinical spaces in commercial or medical office buildings.
Finite element method and dynamical energy analysis in vibro-acoustics - A comparative study
Authors: Zettel Sebastian , Winter René , Norambuena Marco , Böswald Marc , Richter Martin , Tanner Gregor
Published: September 2021

Future aircraft concepts utilizing innovative lightweight structures and novel propulsion concepts are a necessity for long term sustainable air travel. These concepts pose new challenges for the vibro-acoustic assessment of cabin structures and the associated noise impact on passengers.
Finite Element (FE) models derived from aircraft pre-design data are not optimized for use in acoustic analyses, i.e. the mesh is too coarse to provide meaningful results while setting up Statistical Energy Analysis models for this specific purpose is adding another time-consuming step. A
possible alternative, Discrete Energy Analysis (DEA), is evaluated. This method allows to calculate the acoustic behavior of thin-walled structures in higher frequency ranges simply using existing FE meshes. In this paper an experimental lightweight aluminum structure and its respective FE
model is investigated for a frequency range up to 5000 Hz. A comparison in terms of vibrational energy between DEA, FE and measurement results are presented. Finally, a lower-bound frequency range is identified in which DEA and FEM correlate and thus allow a substitution for further simulations
at higher frequencies.
Evaluating worker noise exposure levels in the presence of complex noise
Authors: Murphy William , Qiu Wei , Zhang Meibian
Published: September 2021

Recent research into the assessment of worker noise exposure has demonstrated that the combination of impulsive noise and continuous noise creates an additional risk of developing noise-induced hearing loss (NIHL). Zhang et al (2021) demonstrated that workers exposed to non-Gaussian
noise accumulated NIHL at a faster rate over their careers than worker exposed to Gaussian noise. The kurtosis statistic of the sound pressure distribution provides a means to adjust the estimated risk of hearing loss between exposure groups exposed to different types of noise. This paper
will review the results from our recent studies of kurtosis and exposure level. Some unanswered questions involve the selection of a suitable sample length to estimate kurtosis, the selection of a compensation factor to apply, and understanding the differences exhibited in short (less than
10 years) and long-term exposures and kurtosis.