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Showing 87 results for Acoustic
Volume 0, Issue 0 (2-2024)
Abstract
Defined as a direct, non-conventional link between sound and meaning, the linguistic phenomenon of sound symbolism has empirically been studied for nearly 100 years, and multiple studies have been conducted to reveal the various aspects of the phenomenon. However, no significant studies have done to explain exactly why the phenomenon transpires. That is partly because it has not been studied on the basis of any semantic analysis and/or theory. Nevertheless, the American linguist Edward Sapir first pinpointed the two likely factors that can both or separately be involved in the phenomenon: the acoustic factor, or the articulatory factor (or a combination of both). On the basis of the Conceptual Metaphor Theory (CMT) in Cognitive Semantics, the current paper attempts to explain for the first time how either of the factors or both of them can contribute to the occurrence of the phenomenon. Thus, the question why sound symbolism happens may find a satisfactory answer. Moreover, the answer may pave the way for further theoretical considerations on the potential development of "cognitive" phonology.
Volume 4, Issue 4 (12-2013)
Abstract
Forensic phonetics is a subfield of forensic linguistics in which acoustic information and phonetic features of phones are investigated for completing the forensic cases where one of the existing evidences is related to the guilty. One of the most important tasks of a forensic phonetician is forensic speaker recognition. For doing this, the phonetician is asked to estimate the degree of similarity between the given records of the guilty’s and the suspect’s speech, and determine whether these two sound evidences match to each other or not. The objective of this study, which was conducted on the sound data from 10 Persian native speakers of both sexes, was to investigate the possibility of using Logarithmic spectrographs of vowels as a key for forensic speaker recognition tasks. The results showed that using these logarithmic spectrographs may be a useful means with perfect reliability in the tasks related to forensic speaker recognition.
Volume 4, Issue 4 (2-2024)
Abstract
Problem: Residents of residential complexes in urban areas face all kinds of sounds every day. Most of these hundreds are very noisy and painful in traffic centers.
Target: The aim of the current research is to evaluate the satisfaction of the residents of Tabriz railway neighborhood from the perspective of environmental acoustic comfort.
Method: The current research method is descriptive-analytical with practical purpose. The statistical population of the research is 32,936 residents of the Tabriz railway neighborhood. The sample size was 380 people using Cochran's formula. For the validity of the questions, face validity was used and Cronbach's alpha was used for reliability. To analyze the data, structural equation method and TOPSIS and FTOPSIS techniques from Spss and Amos software were used.
Result: The results showed that among the factors affecting the acoustic comfort of the residents of the Tabriz railway neighborhood, the physical index had the greatest impact, followed by the acoustic and social indicators. Also, the results showed that in terms of the ranking of the koi in terms of acoustic comfort in terms of noise pollution, Ittahad alley got the highest noise pollution, followed by Niloufar alley and Shaghaig koi, the second and third respectively As a result, with proper design and use of form, facade and materials in terms of architectural acoustics, noise pollution can be reduced to a great extent in Tabriz Railway neighborhood and help to improve the quality of acoustic comfort of the residents.
Volume 5, Issue 2 (6-2016)
Abstract
Cicada orni Linnaeus, 1758 is an abundant and common cicada across Europe, North Africa, and western Asia including Iran. The male cicada produces a loud calling song for attraction of females from a long distance. The calling songs are known often to be species-specific and to function in part for species recognition. The present study compares variations in calling song of C. orni in Iran with those reported from other areas and also signifies the importance of calling song in species identification. C. orni were collected in Mazandaran, Iran during summer 2010. Four features were used: echeme duration, echeme period, interecheme interval, number of echeme/s and dominant frequency. Findings of present study showed some resemblance in time and frequency domains in the calling song among the populations of C. orni from Iran and those investigated in Greece, Iberian Peninsula and Turkey. The parameters of calling song showed maximal resemblance with species of Kosmas (Greece). The present results do not support C. orni from Iran as an independent subspecies. Thus, it is concluded that every feature of calling song can be effective in species recognition as is the case for several other parameters.
Volume 8, Issue 3 (8-2017)
Abstract
Teaching/learning French nasal vowels are one of the problems encountered by Iranian teachers and students in institutes and universities. The problems arise due to the fact that there are no approximate phonetic analogues for those vowels in Persian. In the present study, the acoustic phonetics is used. It is a method based on acoustic analysis using speech analysis and phonetics software. In recent years, voice analysis software’s have made it possible to identify phonetic errors with precision. The research objective is to identify French nasal vowels errors by Iranian students and analyze inter-phoneme-phonetic data. The population under study consists 8 students of the French language at University of Isfahan during the first semester 2015-16. Student’s oral productions have been analyzed by using analysis software with regard to structural physical parameters of F1, F2 and F3. As the results of the present study demonstrate, students in the production of French nasal vowels (CVn) are in trouble due to the absence of such vowels in the native language. The process of “unpacking nasal vowels” and “nasalizing the oral vowels” are evident due to the impact of native language. Therefore, the frequency of phonetic errors, French nasal vowels, has a meaningful relationship with the French nasal vowels characteristics and phonetic structure of the students’ native language.
Volume 9, Issue 4 (2-2020)
Abstract
Aims: The present study aims to measure the perceptual quality of sound in the case study of “Darvazeh Isfahan” of Shiraz (a public urban space) in two objective and subjective dimensions.
Participants & Methods: The study method in objective analysis is using acoustic simulation software and measurement of five acoustic components and characteristics of sound including sound pressure level (SPL), sound clarity (C), and sound transmission index (STI). Mental dimension analysis was conducted through direct interviews with people in the space during the day, at three intervals in the morning, noon and afternoon. In the interview process, interviewees were asked to respond to the three components of voice information, voice perception, and auditory rating. Simultaneously, the audio content of the study area was recorded using a calibrated voice recorder.
Findings: The results of the analysis in objective dimension indicate the lack of space acoustic transparency in the contextual and background noise measurement components. Although the audio quality of the sound is normal at all three intervals, in some cases the sound intensity level is poor. The direct sound transmission index is in normal condition. On the subjective side, different audio content was heard over three intervals. In the morning, interviewees identified the buzzing, motorcycling, walking and talking. At noon, in addition to the audio content mentioned, the sound of music was also heard. In the afternoon, motorcycles, cars, and people’s conversations were the main audio content of the space.
Conclusion: Through overlaying the objective and subjective analysis, it has identified the subareas of the study space that have difficulty in perceiving the quality of sound. In summary, location-based urban design solutions for improving perceptual sound quality under problem areas are presented. Despite the fact that the present study might be restricted to a urban space in Shiraz, the findings could impart fruitful information for implicating appropriate acoustic vitality guidelines in urban public spaces.
Participants & Methods: The study method in objective analysis is using acoustic simulation software and measurement of five acoustic components and characteristics of sound including sound pressure level (SPL), sound clarity (C), and sound transmission index (STI). Mental dimension analysis was conducted through direct interviews with people in the space during the day, at three intervals in the morning, noon and afternoon. In the interview process, interviewees were asked to respond to the three components of voice information, voice perception, and auditory rating. Simultaneously, the audio content of the study area was recorded using a calibrated voice recorder.
Findings: The results of the analysis in objective dimension indicate the lack of space acoustic transparency in the contextual and background noise measurement components. Although the audio quality of the sound is normal at all three intervals, in some cases the sound intensity level is poor. The direct sound transmission index is in normal condition. On the subjective side, different audio content was heard over three intervals. In the morning, interviewees identified the buzzing, motorcycling, walking and talking. At noon, in addition to the audio content mentioned, the sound of music was also heard. In the afternoon, motorcycles, cars, and people’s conversations were the main audio content of the space.
Conclusion: Through overlaying the objective and subjective analysis, it has identified the subareas of the study space that have difficulty in perceiving the quality of sound. In summary, location-based urban design solutions for improving perceptual sound quality under problem areas are presented. Despite the fact that the present study might be restricted to a urban space in Shiraz, the findings could impart fruitful information for implicating appropriate acoustic vitality guidelines in urban public spaces.
Volume 10, Issue 1 (4-2010)
Abstract
In this study, generation of the transient evoked ooacoustic emissions in human ear has been simulated using a new electroacoustic model. The method of state variables was adopted to calculate the auditory model, and numerical integration methods have been used to solve differential equations in Matlab. Simulation results have been compared with the real data. In this study, latency curves, frequency spectrum of the simulated TEOAE and calculation errors were used to validate of the model. The results of this research show that simulated outputs are similar to clinical data.
Volume 10, Issue 2 (9-2020)
Abstract
Background: Human comfort involves their physical, psychological and mental comfort. There are several factors that may affect human physical comfort; among them luminous, acoustic and thermal comfort can be mentioned. Usually in researches done in the field of human physical comfort, researchers tried to predetermine human perceived comfort by measuring some physical factors, whilst there are also other ones that can affect human comfort and are necessary to be considered.
Aims: The aim of this paper is to determine the non-physical factors that affect human physical comfort. Another aim is to achieve the model of human physical comfort affected by non-physical factors.
Methods: In this paper by conducting a library research, researches done in the field of non-physical factors that affect human physical comfort were investigated and analyzed; in this way that physical comfort evaluation methods for users of a space, factors affecting it, places in which those researches were done and those researches results were classified and analyzed. In this paper, among factors that can affect human physical comfort, luminous comfort, acoustic comfort and thermal comfort were studied. Analysis method was statistical and by modeling charts and defining oriented trend process in previous researches.
Findings and Conclusion: Findings of this paper indicated that human physical comfort in a space can not be predicted only by relying on physical factors that were usually used in comfort-related indicators.
Aims: The aim of this paper is to determine the non-physical factors that affect human physical comfort. Another aim is to achieve the model of human physical comfort affected by non-physical factors.
Methods: In this paper by conducting a library research, researches done in the field of non-physical factors that affect human physical comfort were investigated and analyzed; in this way that physical comfort evaluation methods for users of a space, factors affecting it, places in which those researches were done and those researches results were classified and analyzed. In this paper, among factors that can affect human physical comfort, luminous comfort, acoustic comfort and thermal comfort were studied. Analysis method was statistical and by modeling charts and defining oriented trend process in previous researches.
Findings and Conclusion: Findings of this paper indicated that human physical comfort in a space can not be predicted only by relying on physical factors that were usually used in comfort-related indicators.
Volume 10, Issue 4 (1-2011)
Abstract
In this paper, for the purpose of investigating horizontal sound propagation, based on the results obtained from practical measurements in the Strait of Hormoz and available data on sound speed variations at different depths, a comprehensive model for shallow water multipath underwater acoustic channel is presented. Mathematical modeling of multipath effect is based on ray theory and the image method. In channel modeling, attenuation due to wave scatterings at the surface and bottom reflections is considered. In addition, we also consider attenuations due to the absorption of sound by different materials and the presence of ambient noises such as the sea state noise, shipping noise, thermal noise and turbulence noise. Then, complete underwater communication system consisting transmitter, channel and receiver was simulated. We use QPSK modulation. Data is transmitted at a rate of 5 kbit/sec with a carrier frequency of 27 kHz, for a maximum range of 1km. The channel estimation is based on a training sequence which occupies about 10% of the signal bit rate.
Volume 10, Issue 5 (11-2019)
Abstract
Consonant clusters that are composed of / R / and other consonants are among the phonetic properties of the French language. Although in the L1 of Persian language learners the syllabic structure of CC is at the end of a Word (but not at the beginning), the correct pronunciation of consonant clusters has always been a difficult task for beginner level learners and even sometimes for higher level learners. Using acoustic phonetics, this study investigated the physical structure of the two consonant clusters of [pR] and [tR] in the French language. A hypothesis could be made that Iranian FFL learners, especially at elementary levels, have a problem in reproducing consonant clusters at the beginning of the target French Words rather than at the end of these Words. To evaluate this hypothesis, phonetic productions of six first-year students at the University of Isfahan majoring in French language and literature were examined in terms of the first, second and third formants, as well as the energy level. Results demonstrated that the error rate of the learners in the re-production of consonant clusters [pR] and [tR] at the beginning and at the end of a Word has a significant relationship with the level of the marked consonant. Besides, the marked consonant clusters at the beginning and the end of target Words cause a phonetic error.
, Ramin Khamedi, Amir Sharifi, Hassan Ebrahimnejad,
Volume 11, Issue 1 (6-2011)
Volume 11, Issue 1 (6-2011)
Abstract
In this paper a new approach about relation of Acoustic Emission(AE) method and mechanical properties of ferrite-martensite dual phase steels(DPS) has presented. The AE signals from a tensile test using a range of DPS with different volume fractions of martensite (VM)s, in the range of 12–65% VM, were obtained and their AE signals were investigated. In order to better study DPS internal behaviour, a function named “sentry function” was used. The amount of this function depends on the strain energy and acoustic emission energy. the Results show that AE monitoring and sentry function are efficient tools for detection of micromechanisms, consisting of Ferrite-Martensite interface decohesion and/or martensite phase fracture, identifying the correlation of failure mechanisms to microstructure in DPS.
Mostafa Ranjbar, Steffen Marburg,
Volume 12, Issue 2 (6-2012)
Volume 12, Issue 2 (6-2012)
Abstract
This paper introduces a new approach for the reduction of sound radiation from the mechanical structures. A combination of genetic algorithm method and geometry modification concept minimizes the root mean square level of structure borne sound for a square plate over a specific frequency range. The structure’s local geometry modification values at the selected surface key-points considered as design variables. The model is under three non-symmetric harmonic excitations. An iterative approach is used to develop new modified model until when a termination criterium is rached. The results show that this approach could produce significant reduction in the value of radiated sound power level of the structure.
, , Ali Valipour Chahardah Cherik,
Volume 12, Issue 5 (1-2013)
Volume 12, Issue 5 (1-2013)
Abstract
Cavitation is changing liquid phase to gas phase due to decreasing local pressure of flow induced by increasing local velocity. In situation of maximum velocity, some bubbles that contain air and vapor are produced and traveled from point of high pressure to lower pressure, so bubbles are destroyed rapidly and produce acoustic noise. Providing sufficient numerical model for simulation of acoustic waves induced by cavitation or supercavitation is so important for monitoring and controlling of these phenomena. For analyzing propagation of acoustic waves in fluid, sound is part of fluid dynamics, so momentum, energy and mass conservation equations like fluid dynamics are basics equation for identification of supercavitation. In this paper, to provide a numerical model contains hydrodynamic and acoustic parts of fluid dynamics, first by using scaled analysis, non dimensional forms of conservation equations are generated. Then by using perturbation method and considering acoustic term as a term in lower order than hydrodynamic term, conservation equations can be separated to two group equations with different orders. Leading order is hydrodynamic equations and first order is acoustic form of conservation equations. Results in first order equation show coupling of acoustic terms with hydrodynamic terms of fluid flow.
Volume 13, Issue 2 (5-2022)
Abstract
The acoustic information can be evidence for many considered matters in other linguistics areas, especially in spoken morphology and speech processing. The present study investigates the Persian derivational words of prefixes and the degree of parsability in processing, understanding, and receiving the meaning of derived words by some acoustic evidence. For this reason, the derived words of the prefixes «nɑ», «ham», and «farɑ» and their bases were extracted from the Institute of Humanities. We chose two parsable and non-parsable derived words of each derivational prefix and put them in carrier sentences. Then, We investigate the acoustic features such as duration, pitch, formants, intensity, duration of maximum intensity, and the clarity of transition point The results show that the relative duration of parsable words is more than non-parsable words. The degree of co-articulation in pitch frequency, first, second, and third formant frequency of non-parsable words in transition points of affix and base and statically position of affix is more than parsable words because of incorporation and without potential pauses. In non-parsable words, the relative maximum duration of intensity is more with the smooth trend. So, the clarity of formants in parsable words is more than in non-parsable words at the transition points.
1. Introduction
According to the presence of the structure of derived words in spoken language, the mental lexical processing can be assessed by its phonetic expression and the variations of morpho-phonetic structures can be surveyed in derived words. According to Plag (2014), we can use morpho-phonetic variations for morphological theories and lexical processing. Hay and Bayeen (2003) through the investigation of phonotactics in parsable and non-parsable derived words in the Complexity-Based Ordering approach considered that in non-parsable words the boundary of affix and base is not discerned very easily due to the affix and base are in phonological Entanglement and during the morphological processing, it’s considered as a whole word because the frequency of the derived word is more than the frequency of its base. This approach by using spoken morphology criteria provides some proofs based on the parsability of the base from the affix. In this regard Hay (2007), Plag and et. (2017) by using the acoustic feature of duration investigated the co-articulation of parsable words. They believed that the co-articulation in non-parsable words is more than the parsable words because in non-parsable words the effect of the adjacent phoneme in the transition point is more.
2. Research Hypothesis
This study tries to answer the question of whether in Persian derived words the acoustic features of duration, pitch, intensity, and clarity of the transition point of affix and base can explain the degree of parsability. The results of this research can be used in the theories of the mental lexicon, speech producing, understanding, and perception of the lexical meaning.
3. Research Method
In the present study, we chose three prefixes of «nɑ-», «ham-», and «farɑ-» from Hemasian (2019). We selected two derived words of each prefix in the way that the non-parsable derived word with high token frequency is placed below the trend line of its scatter plot and the parsable derived word with high token frequency is placed above the trend line of its scatter plot. The chosen words are Hamdasti and Hamdardi, Namardi and Namaree, Foruraftan, and foruravande. For creating the same situation of speech we put the derived words in the same carrier sentences and the same position.
4. Result
In this study, we investigate some acoustic evidence in the degree of parsability for Persian-derived words. For determining whether the duration feature can have any effect on the perception of the degree of parsability of affix from the base, it was found that affix and base duration and relative duration in non-parsable derived words are less than parsable words. Also, the duration differentiation of the last phoneme of the prefix and the first phoneme of the base in non-parsable words are more than in parsable words. These results are in accordance with Hay (2007). Then our hypothesis based on the duration of Persian derived words can be used as a piece of evidence for the degree of parsability is confirmed. In responding to this question that the pitch and formants can be described the morphological structure of derived words according to the transition point in the attachment slot of the affix to the base and the static position of the affix, it showed that the degree of co-articulation in non-parsable words based on the continuity and no potential pause is more. For answering the effect of intensity on the morphological structure of derived words according to findings it determined that in non-parsable words raising duration is more and intensity is very smooth to reach maximize. Then our hypothesis based on the relative raising intensity in non-parsable words is confirmed. In responding to the degree of derived words parsability and the relation with clarity of transition point and with concerning the formants by mapping spectrum it found that the clarity in a transition point in parsable words is more than in non-parsable words. Also, in the transition point, we can see the beginning of the next phoneme very easily. Ultimately, it was found that we can determine the degree of parsability in prefixed derived words by acoustic evidence.
Volume 13, Issue 2 (5-2022)
Abstract
Voicing is one of the most important phonological features in distinguishing consonants in many languages. In this study, we investigated the temporal parameters such as constriction duration, voice duration, and vowel duration in stop and fricative consonants of Azeri Turkish language in intervocalic position (VCV). The main purpose of this study is to study stop and fricative consonants in Tabrizi dialect. An attempt was made to answer the question of how the voicing of stop and fricative consonants of Turkish language affects the temporal parameters. Twelve selected words of Turkish common words were repeated by fourteen Tabrizi speakers. They were produced three times in citation form. The results showed that temporal parameters are considered as potential cues in distinguishing voiced and voiceless Turkish consonants. The results related to stop consonants also showed that only voice duration and vowel duration were effective in the voicing contrast. The results for the closure duration confirmed that there is no significant difference between voiced and voiceless stops and this cue can not be used as a distinguishing cue to voicing in Azeri Turkish stops.
1. Introduction
Glottis and its condition is one aspect of describing consonants; So the vibration in vocal cords during consonant production produces voiced sounds unless the produced sound is voiceless. Voicing is one of the phonological features that has been discussed in most languages and has certain acoustic cues. Some of these cues are defined as temporal features, which include constriction duration, voice duration, and the preceding vowel duration. In other words, these temporal features are considered cues for distinguishing obstruent consonants. Steriade (1997, pp. 6-7) offers a list of cues to voicing and their distribution and believes that changing stop consonants’ position in a syllable can cause a change in the number of voicing cues. closure duration and closure voicing are two essential cues to study stop consonants voicing. Moreover, there are sixteen acoustic features classified into three groups including pre-closure, closure, and post-closure features (Lisker, 1986). Lisker (1986) argues that these features are potentially perceptual cues to voicing distinction in the intervocalic position. This means that closure duration and voice duration are associated with closure, and vowel duration relates to pre-closure features.
Turkish language is one of the most common languages in the Altaic language family which has the largest number of speakers (Crystal, 1987, p. 307). The southwestern branch is one of the main branches of Turkish language, which includes Azerbaijani, Turkish, and Turkmen (Hayat, 2001, p. 8). In general, the Turkish language of Azerbaijan can be divided into two dialects: the northern dialect in the Republic of Azerbaijan and the southern dialect in Iranian Azerbaijan (Johanson, 1998). Among the common non-Persian languages in Iran, Azerbaijani Turkish with 15 to 20 million native speakers has the highest number of speakers (Crystal, 2010) and also among 26 types of Azeri dialects, Baku, Guba, Lankaran, Shirvan, and Tabrizi dialects are common in East Azarbaijan region (Heyat, 2001). This language is agglutinative and has 24 consonants and 9 vowels. Vowels are /ɑ, ɯ, o, u, æ, e, i , œ, y/. Also out of 24 consonants, there are 6 stop consonants / b, p, d, t, ɡ, ɟ / and 9 fricative consonants /f, v, s, z, ʃ, ʒ, x, ɣ, h/ in this language. Additionally, there are two other stops /c/ and /k/ that are used only in the Southern dialect and in loan words (Ghaffarvand Mokri and Warner, 1396).
The main purpose of this study is to examine stop and fricative consonants of Azeri Turkish in the Tabrizi dialect, acoustically. So that these consonants will be evaluated by measuring acoustic cues such as closure duration, voice duration, and vowel duration in intervocalic position. This is an experimental study that will be performed by designing a production test. In this study, we aim at providing an answer to the following question: whether voicing has a significant effect on the duration of acoustic cues in stop and fricative consonants in Azeri Turkish language? We assume that the duration of above-mentioned cues is significantly influenced by voicing feature of obstruents.
2. Literature Review
There are several studies done on many languages evaluating acoustic cues in obstruent consonants such as stop closure duration (Shen et al., 1987; Lisker, 1957; Nikrahi, 2012; Razavi Najafabadi & Nourbakhsh, 2013), fricative constriction duration (Jongman, 2000; Nartey, 1982; Klatt, 1976; Baum &Blumstein, 1987; Rahimi, 2013), affricate closure and frication duration (Hosseinpoor Damirchan & Nourbahsh, 2021), voice onset time (Jahan, 2009; Ünal-Lugacev et al, 2018) and vowel duration ( Ladefoged, 2006, p. 58; Chen, 1970; Raphael, 1972; Warren & Marselen-Wilson, 1989).
3. Methodology
Fourteen Azeri native speakers participated in the production experiment. Twelve Turkish words containing 4 stops /d, t, b, p/ and 8 fricatives /z, s, ʒ, ʃ, ɣ, x, v, f/ were produced in the intervocalic position between vowels /ɑ/. Participants were in a quiet room and produced syllables three times in citation form and also they were asked to repeat with a short interval between each word. Thus, 504 data were obtained (14 speakers × 12 words × 3 repetitions). Praat voice Analysis Software Version 6 .1. 30 were used for acoustic analysis of data. All measurements were done manually considering both waveforms and spectrograms. Also, SPSS software Version 23 was employed for statistical analysis.
4. Results
4-1. Stop closure duration and Frication duration
Closure duration in stop consonants provides two main acoustic information associated with the voicing feature. Examining this cue showed that the length of closure is not significantly longer in viceless stops than voiced (p ≥0.05). The mean closure duration is 93.87 and 98.86 for voiced and voiceless stops respectively. Therefore, closure duration can not be considered a proper acoustic cue to contrast voicing in Azeri Turkish stops.
The results of frication length measurement showed that voiceless fricatives (mean duration: 161.7) are longer than voiced fricatives (mean duration: 91.58). Mean and standard deviation are shown in table 2 for each fricative. The longer duration of voiceless fricatives is significant (p ≤ 0.05) and leads to the result that length of frication is an important cue to fricatives voicing. Table 1 shows descriptive statistics of stops closure duration and fricative constriction duration.
Table 1.
Descriptive statistics of constriction duration in stops and fricatives
| Mean | SD | Min | Max | ||
| Stop | voiced | 93.87 | 16.88 | 58 | 145 |
| voiceless | 98.86 | 23.26 | 48 | 148 | |
| fricatives | voiced | 91.58 | 24.38 | 50 | 166 |
| voiceless | 161.7 | 25.54 | 104 | 218 | |
Mean and standard deviation are shown in table 2 for stop and fricative consonants. The average voice duration obtained for voiced stops is 57.79 which is longer than voice length in voiceless stops with 25.13, therefore the significant difference between voiced and voiceless stops (p ≤ 0.05) demonstrates that voice length is the main cue to voicing recognition.
The overall average voice duration for voiced fricatives is longer than the voiceless with 86.33 and 29.93 respectively. In other words, voiceless fricatives have shorter voice length and this difference is considerably significant (p ≤ 0.05). Thus, voice duration is considered an important cue to voicing category of fricatives.
Table 2.
Descriptive statistics of voice duration in stops and fricatives
| Mean | SD | Min | Max | ||
| Stop | voiced | 57.79 | 27.37 | 10 | 112 |
| voiceless | 25.13 | 11.45 | 7 | 63 | |
| fricatives | voiced | 86.33 | 26.32 | 17 | 166 |
| voiceless | 29.93 | 10.89 | 10 | 80 | |
4-3. Vowel duration preceding stops and fricatives
Mean and standard deviation of vowel length before stops and fricatives are shown in table 3 and indicate that length of vowel before voiced consonants are longer than voiceless ones. The significant difference of voiced and voiceless stops and fricatives (p ≤ 0.05) shows that the duration of vowel precesing obstruens is an essential cue to the voicing distinction.
Table 3
Descriptive statistics of vowel duration before stops and fricatives
| Mean | SD | Min | Max | ||
| Stop | voiced | 114.87 | 23.43 | 60 | 184 |
| voiceless | 96.94 | 23.02 | 59 | 170 | |
| fricatives | voiced | 135.74 | 32.34 | 76 | 234 |
| voiceless | 101.33 | 23.11 | 53 | 159 | |
6. Conclusion
In this study, three acoustic cues in stop and fricative consonants voicing were investigated for speech production in Azeri Turkish language spoken in Tabriz. Except for stop closure duration, the other cues showed significant differences between voiced and voiceless obstruents. Hence, frication duration, voice duration, and vowel duration before obstruents are potential cues to voicing distinction in Turkish language in Tabrizi dialect.
Mohsen Emami, Mohammad H Sadeghi,
Volume 13, Issue 14 (3-2014)
Volume 13, Issue 14 (3-2014)
Abstract
Ultrasonic technology has been applied in many industrial processes such as ultrasonic machining, welding, cutting, sewing, homogenizing, etc. In an ultrasonic system, acoustic horn transmits the vibration energy of ultrasonic transducer to the application area and amplifies the oscillation amplitude. Depending on the application and industrial operating conditions, different horns with different geometries and magnifications are required to be designed. In the present study exponential horns with rectangular cross-section for application in ultrasonic assisted grinding process are designed and analyzed. An analytical approach is applied to model this type of horns. For evaluating the analytical model, some acoustic horns are designed using analytical method and then analyzed by the finite-element method (FEM) in ANSYS. Then, their design parameters such as resonance frequency and amplification factor are compared and verified. A very good agreement is obtained between the results of analytical modeling and those of FEM simulation. Furthermore, geometrical modification was introduced as a solution to coincide the vibration related parameters of the horn to the desired design values. Moreover, a horn-workpiece assembly for applying in ultrasonic assisted grinding was simulated.
Navid Zarif Karimi, Hossin Heidary, Mahdi Ahmadi Najafabadi, A Rahimi, Mehdi Farajpur,
Volume 13, Issue 15 (3-2014)
Volume 13, Issue 15 (3-2014)
Abstract
Drilling of composite materials is one of the major processes in the manufacturing and assembly of sub-component. However, drilling of composite laminates can cause several damages such as degradation in residual tensile strength. In this study, effects of cutting speed, feed rate and drill angle on residual tensile strength of drilled laminates has been investigated. For this purpose, the Taguchi method was employed for three factors at three levels. Acoustic emission signals and wavelet analysis are used to monitor residual tensile strength. The experimental results indicated that the feed rate has the most significant effect. Based on time-frequency analysis of AE signals, it was found that AE signals with frequency ranges of (62.5-125), (250-312.5) and (312.5-375) KHz were generated from matrix cracking, fiber slipping and fiber breakage respectively.
Ramin Khamedi, Esmaeil Porsaeidi, Moosa Jabbari,
Volume 14, Issue 2 (5-2014)
Volume 14, Issue 2 (5-2014)
Abstract
Acoustic Emission technique is a non destructive method which can be used for detection of corrosion mechanism. In this paper the corrosion of sulfuric and hydrochloric acids solution on some kinds of stainless steel like 304, 316 and GTD-450 with and without residual stress was surveyed by acoustic emission technique. Considering tests diagrams, cumulative counts in the samples with residual stress is more than other ones due to high sensitivity of stainless steel samples to stress corrosion cracking. Also frequency in the samples with residual stress is lower than other ones. Cumulative count in the stainless steel 304 is more than stainless steel 316 for all of the samples. A sudden and intensive corrosion in the hydrochloric acid environment was observed specially in the samples with residual stress. For stainless steel 304, this event was very harmful, because, it will the cause of some pitting corrosion, which concentrates stress in these locations and finally creates crack in structure.
Parinaz Belalpour Dastjerdi, Mohammad Fotouhi, Sakine Fotouhi, Mahdi Ahmadi,
Volume 14, Issue 3 (6-2014)
Volume 14, Issue 3 (6-2014)
Abstract
Delamination is one of the main defects in composite materials. Studying the initiation and propagation of delamination is useful for the design and production of high quality resistant materials. Therefore understanding the behavior of delamination damage and having enough knowledge about that will be helpful. In this study, generated acoustic emission signals from two types of glass/epoxy composite specimens at different layups, [0,90]5s and [0]10, is recorded. After that signals were analyzed by applying strain energy function. The results indicate that specimens at different layups have different stiffness behavior toward damage initiation and growth. Using strain energy function method initiation and growth of delamination can be evaluated. The obtained results provide useful information for the design and production of high quality resistant composite materials.