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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Collision Broadening of Microwave Spectral Lines of Monomeric Formaldehyde and Formic Acid

Venkatachar, Arun C. 08 1900 (has links)
Line width parameters for a number of spectral lines in the pure rotational spectrum of formaldehyde (CH20) and formic acid (HCOOH) have been measured using a sourcemodulated microwave spectrograph. All transitions studied in this investigation were of the type ΔJ=O (i.e. Q-branch transitions), with ΔK-1=0 and ΔK+1 =+l. The center frequencies of the measured lines varied from 8662.0 MHz to 48612.70 MHz. The experimentally determined collision diameters for self broadening interactions involving HCOOH and CH2 Q molecules were found to be 2 - 27 per cent less than those calculated by the Murphy-Boggs theory of collision broadening. Much better agreement between a simplified broadening scheme for symmetric top molecules and the observed foreign-gas collision diameters is obtained by using Birnbaum's theory.
2

Perfil espectrográfico e nasométrico da vogal [a] e sua contraparte [ã] em diferentes condições de abertura velofaríngea / Spectrographic and nasometric profiles of the vowel [a] its counterpart [ã] in experimental conditions of the velopharyngeal coupling

Lima, Aveliny Mantovan 04 September 2006 (has links)
A hipernasalidade é uma alteração da ressonância de fala que surge quando há um acoplamento indesejável entre as cavidades oral e nasal durante a fala, geralmente, decorrente de uma disfunção do mecanismo velofaríngeo. A relação entre tamanho da abertura velofaríngea e a hipernasalidade de fala ainda não é um fenômeno bem compreendido. Em particular, pouco se sabe sobre o perfil acústico das vogais em diferentes condições de abertura velofaríngea. O objetivo deste estudo é descrever o perfil espectrográfico e nasométrico da vogal [a] e sua contraparte nasal [ã] durante a produção de fala em condições de abertura velofaríngea diferentes, porém de tamanho controlado. Este estudo foi conduzido por meio da análise acústica e perceptivo-auditiva da fala de um único sujeito com fissura pós-forame incompleta, usuário de uma prótese de palato obturadora, onde o controle do tamanho da abertura velofaríngea foi feito por meio de orifícios de 10 \'MM POT.2\', 20 \'MM POT.2\' e 30 \'MM POT.2\', criados experimentalmente no bulbo de réplicas da prótese deste sujeito. Dois pares mínimos de vogal oral versus vogal nasal inseridos em frase-veículo foram usados como corpus para coleta das amostras de fala, totalizando um número de 136 amostras analisadas neste estudo. O controle do tamanho da abertura velofaríngea (tamanho do gap) mostrou-se uma variável importante na definição do perfil acústico da fala hipernasal, embora não tenha havido linearidade entre os tamanhos de abertura velofaríngea e o grau de nasalância, nem com valores formânticos ou de duração. / Hypernasality is a resonance disorder due to the coupling between the oral and nasal cavities, usually associated to velopharyngeal dysfunction. The relationship between size of velopharyngeal opening and speech hypernasality is not a well understood phenomenon. Particularly, little is known between the acoustic profiles of vowels under differents conditions of velopharyngeal opening. The objective of this study is to describe the acoustic profile of the vowel [a] and its counterpart [ã], during speech production under different, but controlled, sizes of velopharyngeal opening. This study involved the acoustic and auditory-perceptual analysis of the speech of a single subject with incomplete operated cleft palate and a remaining velopharyngeal insufficiency treated with a speech bulb. The subjects speech appliance was duplicated allowing for the introduction of openings of controlled sizes in the bulb (10 \'MM POT.2\', 20 \'MM POT.2\' e 30 \'MM POT.2\'). Two minimal-pair words with the vowel [a] and two with the vowel [ã] produced within a phrase were used as speech corpus leading to a total of 136 speech samples analyzed in this study. Controlling size of velopharyngeal opening was important in the definition of the acoustic profile og hypernasal speech, however, the results of this study did not indicate a linear relation between size of velopharyngeal opening and nasalance scores not with formant or duration measures.
3

Perfil espectrográfico e nasométrico da vogal [a] e sua contraparte [ã] em diferentes condições de abertura velofaríngea / Spectrographic and nasometric profiles of the vowel [a] its counterpart [ã] in experimental conditions of the velopharyngeal coupling

Aveliny Mantovan Lima 04 September 2006 (has links)
A hipernasalidade é uma alteração da ressonância de fala que surge quando há um acoplamento indesejável entre as cavidades oral e nasal durante a fala, geralmente, decorrente de uma disfunção do mecanismo velofaríngeo. A relação entre tamanho da abertura velofaríngea e a hipernasalidade de fala ainda não é um fenômeno bem compreendido. Em particular, pouco se sabe sobre o perfil acústico das vogais em diferentes condições de abertura velofaríngea. O objetivo deste estudo é descrever o perfil espectrográfico e nasométrico da vogal [a] e sua contraparte nasal [ã] durante a produção de fala em condições de abertura velofaríngea diferentes, porém de tamanho controlado. Este estudo foi conduzido por meio da análise acústica e perceptivo-auditiva da fala de um único sujeito com fissura pós-forame incompleta, usuário de uma prótese de palato obturadora, onde o controle do tamanho da abertura velofaríngea foi feito por meio de orifícios de 10 \'MM POT.2\', 20 \'MM POT.2\' e 30 \'MM POT.2\', criados experimentalmente no bulbo de réplicas da prótese deste sujeito. Dois pares mínimos de vogal oral versus vogal nasal inseridos em frase-veículo foram usados como corpus para coleta das amostras de fala, totalizando um número de 136 amostras analisadas neste estudo. O controle do tamanho da abertura velofaríngea (tamanho do gap) mostrou-se uma variável importante na definição do perfil acústico da fala hipernasal, embora não tenha havido linearidade entre os tamanhos de abertura velofaríngea e o grau de nasalância, nem com valores formânticos ou de duração. / Hypernasality is a resonance disorder due to the coupling between the oral and nasal cavities, usually associated to velopharyngeal dysfunction. The relationship between size of velopharyngeal opening and speech hypernasality is not a well understood phenomenon. Particularly, little is known between the acoustic profiles of vowels under differents conditions of velopharyngeal opening. The objective of this study is to describe the acoustic profile of the vowel [a] and its counterpart [ã], during speech production under different, but controlled, sizes of velopharyngeal opening. This study involved the acoustic and auditory-perceptual analysis of the speech of a single subject with incomplete operated cleft palate and a remaining velopharyngeal insufficiency treated with a speech bulb. The subjects speech appliance was duplicated allowing for the introduction of openings of controlled sizes in the bulb (10 \'MM POT.2\', 20 \'MM POT.2\' e 30 \'MM POT.2\'). Two minimal-pair words with the vowel [a] and two with the vowel [ã] produced within a phrase were used as speech corpus leading to a total of 136 speech samples analyzed in this study. Controlling size of velopharyngeal opening was important in the definition of the acoustic profile og hypernasal speech, however, the results of this study did not indicate a linear relation between size of velopharyngeal opening and nasalance scores not with formant or duration measures.
4

Acoustic properties of low growing plants

Horoshenkov, Kirill V., Khan, Amir, Benkreira, Hadj January 2013 (has links)
No / The plane wave normal incidence acoustic absorption coefficient of five types of low growing plants is measured in the presence and absence of soil. These plants are generally used in green living walls and flower beds. Two types of soil are considered in this work: a light-density, man-made soil and a heavy-density natural clay base soil. The absorption coefficient data are obtained in the frequency range of 50-1600 Hz using a standard impedance tube of diameter 100 mm. The equivalent fluid model for sound propagation in rigid frame porous media proposed by Miki [J. Acoust. Soc. Jpn. (E) 11, 25-28 (1990)] is used to predict the experimentally observed behavior of the absorption coefficient spectra of soils, plants, and their combinations. Optimization analysis is employed to deduce the effective flow resistivity and tortuosity of plants which are assumed to behave acoustically as an equivalent fluid in a rigid frame porous medium. It is shown that the leaf area density and dominant angle of leaf orientation are two key morphological characteristics which can be used to predict accurately the effective flow resistivity and tortuosity of plants.
5

Auditory Filters Measured at Neighboring Center Frequencies

Fagelson, Marc A., Champlin, C. A. 01 June 1997 (has links)
Auditory filters were derived in 20 normal-hearing human listeners at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the roex (p,r) method. Comparisons were made between slopes of the filters' skirts at the neighboring CFs with filter output levels of 45 and 70 dB. The same comparisons were made with regard to filter equivalent rectangular bandwidth (ERB). In the 1000-Hz region, the low-frequency slopes (Pl) of filters centered at 913 and 1095 Hz were significantly correlated at both stimulus levels, while the high-frequency slopes (Pu) were similar only at the high test level. In the 4000-Hz region, for sinusoids of 3651 and 4382 Hz, the level effect was clearer as both Pu and Pl values diverged at the low level but were related at high levels. The ERBs centered at the same CFs displayed a similar level dependence. At the stimulus level most likely to be affected by an active feedback mechanism, auditory filters centered at nearly the same frequency displayed quite distinct frequency selectivity, and this trend was stronger in the 4000-Hz region than the 1000-Hz region. The findings suggest that a saturating, active cochlear mechanism may not be distributed evenly, or contribute to peripheral tuning with equal effectiveness throughout the length of the partition.
6

O comportamento vocal entre escolares com queixas vocais, com e sem história de situação de rua, em Aracaju, Brasil

Sales, Neuza Josina 22 May 2006 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objective: it is to compare the frequency of vocal, acoustical and otorhinolaryngological alterations among students who present vocal complaints and street background or not. Method: cross sectional with control group. A random sample of 200 students with a street situation background was selected, aging from 07 to 10, both male and female and all took part in a playful workshop with interviews and vocal assessment afterwards. Out of them, 106 were identified as having voice alteration and/or vocal complaint, which became the study group. This group was then sent to a speech evaluation (hearing perception analysis and spectrography) and an otorhinolaryngological evaluation (physical examination and flexible videonasopharyngealaryngoscopy). The same procedures were performed in 400 students with no street situation background and, after a vocal assessment there were a total of 90 children which became the control group. Results: in the vocal assessment there was a higher incidence of vocal complaints related and/or identified in the risk group accounting 106 (17%) children who also presented characteristics of professional use of spoken voice. In the functional speech diagnosis the control group presented higher incidence of dysphonia accounting 73 (37%) in relation to the risk group. The acoustical analysis presented significant difference (p<0,01) between the two groups. In the otorhinolaryngological evaluation there was equal distribution, among the groups, of otological pathologies accounting 12 (8%), pharyngeal tonsil hypertrophy accounting 100 (67%) and varied laryngeal pathologies. The control group presented higher incidence of palato tonsil hypertrophy accounting 18 (12%) and in the risk group there was a higher incidence of nasal alterations accounting 52 (34%) and triangular medium posterior glottic gap accounting 30 (20%). Conclusion: in the control group there was a higher incidence of hoarseness, harshness and breathiness at a discrete and moderate degree and strained quality voice at a moderate degree associated to palato tonsil hypertrophy and computer acoustical parameters of significantly poor quality in relation to the risk group. The risk group makes professional use of spoken voice with high incidence of normal voice, nasal alterations and triangular medium posterior glottic gap, besides computer acoustical parameters of significantly higher quality in relation to the control group. / Objetivo: Comparar a distribuição das alterações vocais, acústicas e otorrinolaringológicas entre escolares com queixas vocais, com ou sem história de situação de rua. Método: transversal com grupo controle. Foi selecionada uma amostra aleatória de 200 escolares com história de situação de rua, com idade entre 07-10 anos, de ambos os sexos. Todos participaram de oficina lúdica, com entrevista e triagem vocal posterior. Destas, 106 crianças foram identificadas com alteração vocal e/ou relataram queixa vocal que se constituiu no grupo de estudo. Este grupo foi encaminhado para avaliação fonoaudiológica (análise perceptivo-auditiva e espectrografia) e avaliação otorrinolaringológica (exame físico e vídeonasofaringolaringoscopia flexível). Os mesmos procedimentos foram realizados com 400 escolares, sem história de situação de rua e após triagem vocal formou-se um total de 90 crianças que se constituiu no grupo controle. Resultados: Na triagem vocal houve significância de queixas vocais relatadas e/ou identificadas em 106 (17%) crianças do grupo de risco e que também apresentou características de uso profissional da voz falada No diagnóstico fonoaudiológico o grupo controle apresentou significância de disfonia em 73 (37%) crianças em relação ao grupo de risco. Na análise acústica computadorizada houve diferenças significativas (p<0,01) entre os dois grupos. Na avaliação otorrinolaringológica ocorreu distribuição igual entre os grupos de alterações otológicas 12 (8%), hipertrofia de tonsila faríngea 100 (67%) e alterações laríngeas variadas. O grupo controle apresentou significância de hipertrofia de tonsila palatina 18 (12%) e no grupo de risco ocorreu significância de alterações nasais 52 (34%) e fenda glótica triangular média posterior 30 (20%). Conclusão: No grupo controle, houve significância no tipo de voz rouca, áspera, soprosa grau discreto e moderado e, voz tensa grau moderado associado à hipertrofia de tonsila palatina e parâmetros acústicos computadorizados com qualidade significantemente inferiores em relação ao grupo de risco. O grupo de risco faz uso profissional da voz falada com significância de voz normal, alterações nasais e fenda glótica triangular média posterior além de parâmetros acústicos computadorizados com qualidade significantemente superior em relação ao grupo controle.

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