ACOUSTIC EVALUATION OF A WATER-COOLED FLAME BUCKET

1961 ◽  
Author(s):  
A. L. Shulman
Keyword(s):  
Acoustic Evaluation

scholarly journals Correction to: A preliminary acoustic evaluation of three sites in the lagoon of Bora Bora, French Polynesia

2021 ◽  
Author(s):  
Frédéric Bertucci ◽  
Ana Sofia Guerra ◽  
Vincent Sturny ◽  
Eric Blin ◽  
Gaston Tong Sang ◽  
...  
Keyword(s):  
French Polynesia ◽  
Acoustic Evaluation

Acoustic Analysis of Voice in Singers: A Systematic Review

2018 ◽  
Vol 61 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Dhanshree R. Gunjawate ◽  
Rohit Ravi ◽  
Rajashekhar Bellur
Keyword(s):  
Systematic Review ◽  
Acoustic Analysis ◽  
Data Extraction ◽  
Severity Index ◽  
Sound Studies ◽  
Singing Voice ◽  
Inclusion Criteria ◽  
Acoustic Measures ◽  
Great Heterogeneity ◽  
Acoustic Evaluation

Purpose Singers are vocal athletes having specific demands from their voice and require special consideration during voice evaluation. Presently, there is a lack of standards for acoustic evaluation in them. The aim of the present study was to systematically review the available literature on the acoustic analysis of voice in singers. Method A systematic review of studies on acoustic analysis of voice in singers (PubMed/MEDLINE, CINAHL, Scopus, ProQuest, Cochrane, Ovid, Science Direct, and Shodhganga) was carried out. Key words based on PIO (population–investigation–outcome) were used to develop search strings. Titles and abstracts were screened independently, and appropriate studies were read in full for data extraction. Results Of the 895 studies, 26 studies met the inclusion criteria. Great variability was noted in the instruments and task used. Different acoustic measures were employed, such as fundamental frequency, perturbation, cepstral, spectral, dysphonia severity index, singing power ratio, and so forth. Conclusion Overall, a great heterogeneity was noted regarding population, tasks, instruments, and parameters. There is a lack of standardized criteria for the evaluation of singing voice. In order to implement acoustic analysis as a part of comprehensive voice evaluation exclusively for singers, there is a certain need for methodical sound studies.

Acoustic evaluation of surgical intervention for one speech therapy patient

1994 ◽  
Vol 96 (5) ◽  
pp. 3229-3229
Author(s):  
Robert Hagiwara ◽  
Susan Meyers Fosnot ◽  
David M. Alessi ◽  
Gerald M. Sloan
Keyword(s):  
Speech Therapy ◽  
Surgical Intervention ◽  
Acoustic Evaluation

scholarly journals Laryngeal and Vocal Characterization of Asymptomatic Adults With Sulcus Vocalis

2019 ◽  
Vol 23 (03) ◽  
pp. e331-e337 ◽  
Author(s):  
Alex Bruno Soares ◽  
Bruno Teixeira de Moares ◽  
Ana Nery Barbosa de Araújo ◽  
Noemi Grigoletto de Biase ◽  
Jonia Alves Lucena
Keyword(s):  
Auditory Perception ◽  
Control Group ◽  
Type I ◽  
Self Assessment ◽  
Acoustic Evaluation ◽  
Sulcus Vocalis ◽  
Vocal Quality ◽  
The Voice ◽  
Experimental Group

Introduction Sulcus vocalis is defined as a longitudinal depression on the vocal cord, parallel to its free border. Its most marked characteristic is breathlessness, caused by incomplete glottal closure, in addition to roughness, due to the decrease in mucosal wave amplitude of the vocal cords. Vocal acoustic aspects, such as fundamental voice frequency, jitter, and shimmer, may also be altered in individuals with this type of laryngeal disorder. To assess the voice of individuals with sulcus vocalis, studies generally include a sample of subjects with vocal symptoms, excluding asymptomatic persons. To better characterize the vocal characteristics of individuals with sulcus vocalis, their asymptomatic counterparts must also be included. Objective Characterize the larynx and voice of asymptomatic adults with sulcus vocalis. Method A total of 26 adults, 13 with sulcus vocalis (experimental group) and 13 without (control group) were assessed. All the participants were submitted to suspension microlaryngoscopy, voice self-assessment, auditory perception and acoustic evaluation of the voice. Results Among the individuals with sulcus vocalis, 78% of the sulci were type I and 22% type II. Auditory perception assessment obtained statistically significant lower scores in individuals with sulcus vocalis compared with the control group, and a slight difference in the overall degree of hoarseness and roughness. No statistically significant intergroup diferences were found in self-reported voice or acoustic assessment. Conclusion Type I was the predominant sulcus vocalis observed in individuals without voice complaints, who may also exhibit slight changes in vocal quality and roughness.

Assessment and Optimization of the Aerodynamic and Acoustic Characteristics of a Counter Rotating Open Rotor

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
R. Schnell ◽  
J. Yin ◽  
C. Voss ◽  
E. Nicke
Keyword(s):  
Optimization Procedure ◽  
Operating Conditions ◽  
Far Field ◽  
Multi Objective Optimization ◽  
Automatic Optimization ◽  
Open Rotor ◽  
Acoustic Evaluation ◽  
Definition Of ◽  
Cfd Method ◽  
The Given

The present study demonstrates the aerodynamic and acoustic optimization potential of a counter rotating open rotor. The objective was to maximize the propeller efficiency at top of climb conditions and to minimize the noise emission at takeoff while fulfilling the given thrust specifications at two operating conditions (takeoff and top of climb) considered. Both objectives were successfully met by applying an efficient multi-objective optimization procedure in combination with a 3D RANS method. The acoustic evaluation was carried out with a coupled U-RANS and an analytic far field prediction method based on an integral Ffowcs Williams-Hawkings approach. This first part of the paper deals with the application of DLR’s CFD method TRACE to counter rotating open rotors. This study features the choice and placement of boundary conditions, resolution requirements, and a corresponding meshing strategy. The aerodynamic performance in terms of thrust, torque, and efficiency was evaluated based on steady state calculations with a mixing plane placed in between both rotors, which allowed for an efficient and reliable evaluation of the performance, in particular, within the automatic optimization. The aerodynamic optimization was carried by the application of AutoOpti, a multi-objective optimization procedure based on an evolutionary algorithm, which also was developed at the Institute of propulsion technology at DLR. The optimization presented in this paper features more than 1600 converged 3D steady-state CFD simulations at two operating conditions, takeoff and top of climb, respectively. In order to accelerate the optimization process, a surrogate model based on a Kriging interpolation on the response surfaces was introduced. The main constrains and regions of interest during the optimization were a given power split between the rotors at takeoff, retaining an axial outflow at the aft rotor exit at top of climb, and fulfilling the given thrust specifications at both operating conditions. Two objectives were defined: One was to maximize the (propeller) efficiency at top of climb conditions. The other objective was an acoustic criteria aiming at decreasing the rotor/rotor interaction noise at takeoff by smoothening the front rotor wakes. Approximately 100 geometric parameters were set free during the optimization to allow for a flexible definition of the 3D blade geometry in terms of rotor sweep, aft rotor clipping, hub contour as well as a flexible definition of different 2D profiles at different radial locations. The acoustic evaluation was carried out based on unsteady 3D-RANS computations with the same CFD method (TRACE) involving an efficient single-passage phase-lag approach. These unsteady results were coupled with the integral Ffowcs Williams-Hawkings method APSIM via a permeable control surface covering both rotors. The far field directivities and spectra for a linear microphone array were evaluated, here mainly at the takeoff certification point. This (still time consuming) acoustic evaluation was carried out after the automatic optimization for a few of the most promising individuals only, and results will be presented in comparison with the baseline configuration. This detailed acoustic evaluation also allowed for an assessment of the effectiveness of the acoustic cost function as introduced within the automatic optimization.

Evaluation of WB Coatings by Scanned Imaging Microscopy

2003 ◽  
Author(s):  
Jikai Du ◽  
Bernhard R. Tittmann
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Attenuation Coefficients ◽  
High Attenuation ◽  
Nano Indentation ◽  
Atomic Force ◽  
Acoustic Evaluation ◽  
Acoustic Velocities ◽  
Thick Coatings ◽  
Scanning Acoustic Microscope

Organic thick coatings (epoxy, polyurethane, and acrylic-urethane) have been widely applied to high modulus substrates (e.g., steel) for anticorrosion protection. To improve performance, reinforced components (clay, bochmite, nanopaticles, etc.) are usually added to these coatings. However, the acoustic evaluation of these coatings is difficult due to their low acoustic velocities and high attenuation coefficients. In this paper, first, the scanning acoustic microscope (SAM) is used to image sub-surfaces, coating/substrate interfaces, and to measure acoustic velocities. Different phases can be observed on some coatings and defects can be found at some interfaces. Secondly, the atomic force microscope (AFM) is applied to image surfaces at high resolution (compared to SAM). These results agree with SAM images. Thirdly, a nano-indentation technique is utilized to measure the reduced Young’s modulus and absolute hardness of the coatings. The results show that epoxy has the highest Young’s modulus and acrylic-urethane has the lowest. Reinforced components can either increase or decrease Young’s modulus, and hardness depending on the coating material. Finally, results from the SAM, AFM and nano-indentation are compared and analyzed to optimize the evaluation.

Acoustic evaluation of vowels produced by hearing‐impaired children

1990 ◽  
Vol 88 (S1) ◽  
pp. S175-S175
Author(s):  
Marios Fourakis ◽  
Ann Geers ◽  
Mary Russo ◽  
Emily Tobey
Keyword(s):  
Hearing Impaired ◽  
Acoustic Evaluation ◽  
Impaired Children ◽  
Hearing Impaired Children
Sign in / Sign up

Export Citation Format

Share Document