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Sound produced by vertical axis wind turbines can reduce their popularity for use in urban and residential areas. In order to reduce the produced sound level the acoustic behavior of hybrid rotor is studied in this research with the help of Computational Fluid Dynamics (CFD). In the investigated rotor structure, conventional-type blades were used as the inner rotor, which was connected to the outer rotor at a zero-degree angle. To ensure the modeling, the validation of the results and the measuring of effect of the time step on the output data were undertaken. The purpose of this research was to investigate the effect of a tip speed ratio and free wind speed on the level of sound produced. The results showed that the sound level produced had a direct relationship with a tip speed ratio and the free wind speed in such a way that the lowest sound pressure level in a tip speed ratio of 1.5 and the free wind speed of 5 m/s was reported by the R4 receiver. Its value was equal to 7.64 dB. Also, by moving away from the rotor, the produced sound level decreasesd. [ABSTRACT FROM AUTHOR]

Khafi is one of the dialects of Persian which is common in the city of Khaf (situated in Khorasan Province). The Dialect has a number of differences from Standard Persian regarding phonetics, phonology, and morphology. In this article, simple vowels in the Khafi dialect are described and categorized through minimal pairs and according to generative phonological theory. In order to study and perform an accurate and quantitative comparison, an acoustic experiment is carried out involving eight male speakers in the city of Khaf and within the framework of Source-Filter theory, the acoustic features of these vowels are studied and measured in an unstressed open syllable. In this article, first of all, the average frequency of first and second formants (quality acoustic correlates) of simple vowels in Khafi and Standard Persian are presented on the hertz scale and the average duration of these vowels is presented according to the millisecond, then the quantitative difference of acoustic features of the vowels in Khafi from Standard Persian is measured according to percentage and the results are analyzed. Acoustic vowel space in the Khafi dialect is drawn. In order to study these vowels concerning auditory, the quantity of first and second formants are changed from hertz to auditory and non-linear Bark measurement and are shown in a table then based on these numbers and in order to study the similarities and differences more accurately, Euclidean distance of the vowels in Khafi with the vowels in Standard Persian are calculated.

in this paper, design, implementation and test of 24 bit acoustic DAQ subsystem for bio-capsule of Pajohesh explorer is presented. the proposed structure has been used B&K 4942 microphone as input sensing element. the proposed DAQ, has 48Ksps speed, 24 bit resolution, 113dB dynamic range and 23 KHz BW. we used a ARM Cortex M3 for signal handling and processing. the acquiescing data have been sending to Bio- capsule FC and also recorded in a Micro-SD card. power consumption of the proposed DAQ is obtained 2.8W. the proposed DAQ take a place with dimentions of 40*40*100 mm3 inside of bio-capsule stand.

Introduction: Gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) are associated with voice disorders, which cause changes in the structure of the vocal cords and subsequently changes in the voice quality and unpleasant feelings. Since LPR is stronger and has more direct impact on the laryngopharyngeal mucosa and vocal cords than the GERD, it is supposed to create more stable sensory symptoms and acoustic features. Therefore, this study aimed to examine and compare patients with LPR and GERD as well as their acoustic features and vocal tract discomfort (VTD) symptoms. Materials and Methods: This cross-sectional descriptive-analytic study included 17 patients with GERD and 18 patients with LPR. The voices of patients were recorded in an acoustic room (noise 28 dB). Besides, both groups of patients were asked to complete the VTDs. Then, acoustic features were analyzed using praat software. In addition, the frequency and severity scores of the VTDs were analyzed via SPSS software. Results: Baseline frequency, jitter (local), and shimmer (local), and also harmonic-to-noise ratio were not significantly different between the two groups. Meanwhile, the severity of soreness and the frequency and severity of pain were significant between the two groups. Conclusion: The severity and the frequency of pain and the frequency of soreness are more prevalent in patients suffering from LPR than the patients with GERD. LPR has more destructive effects on the acoustic features and the vocal tracts of patients with LPR, due to its stronger involvement with the laryngopharyngeal space. Therefore, patients with voice disorders indicating higher scores than normal in VTD must be examined for LPR, although they do not show symptoms of heartburn or acid reflux.

In this study, 10 samples of beech wood, without apparent defect, with dimensions of 360 × ‎‎16 × 16 ‎cm (length × radial × tangential) were selected, and after being exposed to variable ‎temperature (60, ‎‎80, 100, 120, 140, 160, and 180°C) and moisture content conditions ‎‎(moisture content in conditions ‎of: saturated with water (EMC=35±5%), equilibrium moisture content ‎exposed to air (EMC=19±5%), ‎and conditioning moisture content in a climatic chamber (EMC=12±2%), they underwent free ‎flexural ‎vibration test in two longitudinal-tangential and longitudinal-radial planes‎‏,‏‎ and some ‎of the physical, ‎mechanical, and acoustical properties in both planes‎ were investigated. The ‎results showed that the ‎correlation coefficient of the first three modes of flexural vibration in ‎both planes under ‎climatic ‎chamber had a similar situation, but when the samples were in the ‎water-saturated condition, they ‎showed an adverse behavior in each plane. The effect of ‎increasing the temperature above 100°C ‎caused stresses resulting from shrinkage leading to ‎the development of micro-cracks and reduction in ‎the modulus of elasticity of cell walls and ‎ultimately reduction in wave propagation ability of wood, ‎thus increase in the damping ‎vibration values in both longitudinal-tangential and longitudinal-radial ‎planes of the samples. ‎Also, the concurrent changes in modulus of elasticity and damping vibration in ‎both vibration ‎planes are a desirable indicator for monitoring the process from the primary logging ‎process ‎stages to processes such as wood drying and heat treatment.‎

Introduction Nowadays, many studies were performed about noise source and its type and effects related to duration of sound emission. Most of these researches just report sound pressure level in frequency or time domain. These researches should be continued in order to find better absorber material in noise pollution. Use of fractal geometry is a new method in this filed. Wave fractal dimension value is a strong tool for diagnosis of signal instability and fractal analysis is a good method to finding sound signal characteristics. Therefore the aim of this study is on the fractal geometry of SAMPO 3065 combine harvester signals and determine the fractal dimension value of these signals in different operational conditions by Katz, Sevcik, Higuchi and MRBC methods. Materials and Methods In this research, sound signals of SAMPO 3065 harvester combine that were recorded by Maleki and Lashgari (2014), were analyzed. Engine speed (high and low), gear ratio (neutral, 1st, 2nd, 3rd gear), type of operation (traveling and harvesting) and microphone position (in and out of the cabin) were the main factors of this research. For determining signal fractal dimension value in time domain, wave shape supposed as a geometrical shape and for calculation of fractal dimension value of these signals, total area of wave shape was divided into boxes in 50, 100, 200 milliseconds with an interval 25 millisecond box. Then Fractal dimension value of these boxes was calculated by Katz, Sevcik, Higuchi and MRBC methods using MATLAB (2010a) software. SPSS (Ver.20) software was used for further analysis. Results and Discussion Results showed mean effects of engine speed, microphone position, gear ratio, type of operation, box length, calculation method and all of two way interaction effects were significant. Means of Fractal Dimension in the road and field position were 1.4 and 1.28 respectively. The Maximum growth ratio of fractal dimension value during engine speed levels was related to road position. By increasing of box length and number of data points in each box, the fractal dimension value was increased. Investigation of fractal dimension methods showed changes of box length did not affect fractal dimension value in Higuchi method and range of this factor while box length varied were 0.001, 0.171, 0.005 and 0.024 in Higuchi, Katz, MRBC and Sevcik method respectively. These results showed that Katz method has maximum sensitivity and MRBC method like Higuchi method had the minimum sensitivity by changing of box length. In this research fractal dimension value of SAMPO Combine signals in the time domain in different operation conditions were investigated by Katz, Sevcik, Higuchi and MRBC methods. These values varied from 1 to 1.5 in different conditions. Maximum fractal dimension value was 1.63 in case of no cabin by MRBC method. Increasing of box length or further the data point cause of increasing fractal dimension value with increasing of sound pressure level of combine due to increasing of engine speed and working of different parts of harvesting combine. Due to define of sound pressure level, and increasing of this item in each gear ratio ,this can be justify that in high engine speed, wave turbulent is higher than low speed and this turbulent appeared in fractal dimension value. Conclusions One of the important factors in the evaluation of the time series disturbance is fractal dimension. Therefore, the study of sound signals can be an effective role in this regard. Factors such as the cabin existence, gear type, engine speed and operational state of combining parts had a considerable role in distribution of combinimg sound signals and fractal dimention of these signals. For example cabin acts as a barrier in the sound wave and decrease the sound pressure level near driver ear and cause decrease fractal dimention of signals. The study of time series with different lengths have shown that the duration time of the calculation in various methods had a significant effect. Increasing the length of signals due to a higher number of signal data cause to increase calculation time of fractal dimension calculation, while the changes of fractal dimension in increasing of the number of data is minimum and negligible. Therefore, the choice of the appropriate length of the signal is important.

Introduction Cucumis melo includes a wide range of varieties. The acoustic is production, transmission and energy received form medium vibrations. Acoustic or sonic tests applies for grading productions, ripening determination of fruit firmness and sorting of broken eggs and so on in agriculture. Currently these methods are generalized for measuring non-spherical fruits properties. The primary objective of the present research was to investigate the effect of acoustic system variables such as impact places, impactor material type, pendulum angle and sound level meter position on acoustics response of two different melon varieties, including Zard-Eyvanekey and Sousky-Sabz. These results can be useful for designing acoustic implements related to agricultural products. Materials and Methods This research was conducted on 65 samples of Zard-Eyvanekey and Sousky-Sabz varieties (export varieties). A laboratory recording system used to acquire the acoustic impulse information that was comprised a mechanical excitement mechanism (an impactor such as pendulum), sound level meter, a lap-top computer and software to control the experimental setup and to analyze its results (Cool Edit Pro 2.0 Software), and melon-bed. The impactor consists of diameter and long copper rod 3 mm and 256 mm, respectively. The ball mass was 72.13 gram. The acoustic signal was sensed by a sound level meter (SLM) type 2270 B&K company Denmark. The samples locate on soft cushion for keeping because this bed prevents vibration distortion and causes free vibration. We consider three measurements on equator or mid-section of each fruit (approximately 120 degree) for diminishing inherent diversity of sample shapes. The sound level meter was placed at a distance of 2-5 mm from the fruit surface. The effects of sound level meter, impactor ball and pendulum angle on sound signals were investigated. The effects of other parameters were analyzed by factorial test in randomized complete plot by three replications for each sample. The treatments were 36 and 65 melons of each variety were selected. Results and Discussion The average samples peaks were 10576 and 28663 at 90 and 180 degrees respect to impact place, respectively. Other factors such as impactor ball type (steel), impact angle (70 degrees) and variety type (Zard-Eyvanekey) were constant. The resonance frequency was 123.05 Hz for both SLM position. The averages of peak sound pressure level were 55.29 and 52.38 dB at 90 and 180 degrees positions, respectively. It concluded that the change of sound pressure meter (SLM) position of 90 to 180 degree caused to increase sound pressure level but had no effect on reach the time to peak and resonance frequency. The effect of impactor ball material and impact angle of pendulum on recording signals approximately resemble up and did not state here. The factor levels were sound level meter position respect to impact place (two levels), impactor ball material (three levels) and impact angle of pendulum (three levels). We found that effect of sound level meter position; ball material and impact angle variables on sound pressure level values and interaction effect of sound level meter  impact angle on FFT magnitude was significant at 1% level in both varieties. None of the variables and interactions has effect on the resonance frequency in both varieties. It can be concluded from tables that resonance frequency was more suitable than sound pressure level and FFT magnitude in acoustic tests. The increment of angle caused to increase impact velocity because the length and mass of pendulum rod were constant. We can state the above conclusion about impact velocity (excitement velocity) too, e.g. the impact velocity (excitement velocity) had no effect on resonance frequency while it effected on sound pressure level and FFT magnitude. This conclusion coincides to others researchers. Conclusions The impactor ball, pendulum angle, sound level meter position and variety type factors did not showve significant effect on resonance frequency but they had significant effect on FFT magnitude and sound pressure meter. Because of the high pressure level and measurement easily, it was recommended the position 90 degrees of microphone respect to impact place for acoustics measurements. The maximum sound pressure levels were 54.43, 54.81 and 55.11dB for glass, steel and plastic, respectively. Other factors such as SLM position (180 degrees respect to impact), impact angle (70 degrees) and variety type (Zard-Eyvanekey) were constant. Because of receiving high pressure level from impact angle of 70 degrees respect to 20 and 45 degrees, it was recommended for acoustics measurements. It can be used the lower angles by considering the low background sound.

Introduction: Flaccid dysarthria is a group of motor speech disorders. Muscle weakness and reduced muscle tone, speed, range, and accuracy of speech movements are the primary speech features in these patients. Speech acoustic patterning in these patients shows deficits in motor control including problems in timing, articulatory coordination and laryngeal control. The aim of the present study was to investigate the speech timing through second-formant transition (F2T) acoustic analysis. Materials and Methods: In this descriptive-analytical, cross-sectional and case-control study, ten speakers with flaccid dysarthria and ten speakers without dysarthria were participated. After exposure to the test environment, acoustic signals related to target words including voiced and voiceless stops were collected and recorded. After recording data through the software of Praat, spectrogram of each word was carefully examined to determine the second-formant transition. Results: The people with mild to moderate flaccid dysarthria possessed longer second-formant transition comparing with normal individuals and also differences between the two groups in bilabial and dental consonants were significant (P ≤ 0.05). Conclusion: Increased duration of the second-formant transition in individuals with mild to moderate flaccid dysarthria indicates that in these patients, there are defects in the coordination, timing of movements and articulatory implementation to produce the target segment. In addition, the clinical implication of these results is that different consonants show varying sensitivity to the problem of speech motor control. Speech-language pathologists should pay special attention to duration of second-formant transition (bilabial, dental) and rate of variation in the program for flaccid dysarthria.

Background and Purpose: Lipoid Proteinosis (LP) is a rare hereditary progressive disorder caused by a disorder of collagen metabolism. In LP, hyaline deposits in mucous membrane of true vocal folds causes hoarseness. The studies on the laryngeal and voice features of patients with LP are rare. To the best of our knowledge, this is the first research to study acoustic and perceptual voice features in two Iranian children with LP. Materials and Methods: Two children (siblings) were assessed. The main voice complaint was hoarseness. Voice samples were recorded and acoustically analyzed by Praat. Furthermore, perceptual voice assessment was performed according to the GRBAS scale. Results: Acoustic measurement represented increase in f0, jitter, and shimmer in both children. Furthermore, mean scores of the GRBAS for all voice parameters were more than 60. Conclusion: Current study is the first research that describes the voice features of Persian subjects with LP. Comprehensive understanding of the etiology in voice problems helps speech and language pathologists to provide appropriate clinical services considering the nature of pathological condition to clients.

Spastic dysarthria is a motor speech disorder. It can cause hypernasaliy in speech, inappropriate prosody in speech, misarticulation and variable speech rate which often make the speech unintelligible. In many studies, acoustic analysis has been recommended to determine the type and quality of dysarthria. Most researchers have been introduced acoustic features formant structure as the most important characteristic of physical and perceptual and first, second and third formants have mentioned as the acoustic properties for evaluation of tongue and lips movement restrictions. In this study, we also examined acoustic features of vowel formants in patient with spastic dysarthria and compared with homogeneous healthy person to determine tongue and lips movement characterizes in patient with spastic dysarthria. Results showed that mean of frequencies F1, F2, F3 in patient with spastic dysarthria in comparison with healthy person are significantly different (p= 0/000). Interpretations of results will be discussed in article. [ABSTRACT FROM AUTHOR]

In this study, Clash Voice processing in the field of wavelet and Artificial neural network (ANN) has been evaluated in order to separate hazelnuts according to their size (large, small, medium), and also being filled or empty. Hazelnuts were divided into three size groups (large, medium and small) and each hazelnut of the groups was weighted in order to separate the filled ones from the empty ones. All hazelnuts were then released from 40 and 50 cm height; bopped with a metal plate and Clash Voice was recorded. Signals in the field of wavelet were processed after the Preprocessing. Obtained profiles were applied as input to the ANN. The results showed that Neural Networks with 3 and 9 neurons in the hidden layer could successfully (accuracy of 100%) break up the hazelnuts that were dropped from 40 and 50 cm heights. The filled and empty hazelnuts of large, medium and small groups were separated from each other with the accuracy of 100, 99.61 and 98% for the height of 40 cm and 100, 99.66, 97.5% for the height of 50 cm. This research in combination with the common methods could probably reduce damages; increase the precision and the speed of separation.

The growing use of industrial machinery, household appliances and etc, has increased undesirable noises. Thus, the need to control and reduce the undesirable noises in a closed space has caused a lot of interest in recent years. In this paper, the behavior of sound waves in a closed space is investigated using finite difference time domain method. For this reason, firstly, the wave equation is derived using the mass and momentum conservation equation and adiabatic state equation for an ideal compressible fluid. Then, the boundary condition equation for a closed space is obtained using the momentum conservation law and wall impedance equation. The obtained equations are discritized based on the finite difference time domain method. Finally, the wave equation is solved under the wall boundary condition with arbitrary absorption coefficient and impulse source initial condition. The results show the capability of the method for solving this kind of problems.

Background and Purpose: Lipoid Proteinosis (LP) is a rare hereditary progressive disorder caused by a disorder of collagen metabolism. In LP, hyaline deposits in mucous membrane of true vocal folds causes hoarseness. The studies on the laryngeal and voice features of patients with LP are rare. To the best of our knowledge, this is the first research to study acoustic and perceptual voice features in two Iranian children with LP. Materials and Methods: Two children (siblings) were assessed. The main voice complaint was hoarseness. Voice samples were recorded and acoustically analyzed by Praat. Furthermore, perceptual voice assessment was performed according to the GRBAS scale. Results: Acoustic measurement represented increase in f0, jitter, and shimmer in both children. Furthermore, mean scores of the GRBAS for all voice parameters were more than 60. Conclusion: Current study is the first research that describes the voice features of Persian subjects with LP. Comprehensive understanding of the etiology in voice problems helps speech and language pathologists to provide appropriate clinical services considering the nature of pathological condition to clients. [ABSTRACT FROM AUTHOR]

Sound is a wave pressure which propagates through an elastic or compressible medium. The pressure wave may be produced by vibrations of an elastic structure which is in contact with the medium. Therefore, the propagated wave may be used to collect some useful data about the geometrical and the physical characteristics of the sound source. In this study, a simply-supported rectangular plate stimulated by a harmonic force and attached to a viscous damper in specific locations, is considered. The governing equations of the plate are derived using Lagrange method. Then, these equations are solved employing Helmholtz-Kirchoff integral and Fourier transforms to measure near filed and far-field scattered acoustic pressure. In the sequel, assuming the location of the damper and the applied force to be unknown, the sound recorded by a microphone array is used to identify the force and the damper locations and also to find vibration stream lines, in a reverse manner. Numerical simulations confirm the applicability of the proposed method. The obtained data may be used to suggest proper mechanisms for absorption and damping of the vibration energy. [ABSTRACT FROM AUTHOR]

Relaxation and comfort are two important factors of life, but nowadays life is full of sound both good sounds and unpleasant noises. Mechanical life causes acoustical problems in cities. Urban noise and traffic noise are factors that destroy comfort. Such sounds have negative impacts on people's lives. Use of appropriate methods to reduce noise pollution is one of the most important points that should be considered. Harmful effects of noise pollution on human health will appear in the long term as well as on the environment. Physiological and psychological effects of noise on humans often appear gradually and in the long time, it directly hurts the human nervous system, so in the design of buildings it is needed to provide acoustic comfort. Acoustic is methods of designing spaces, buildings and mechanical systems according to the need of hearing. First we have to know more about hearing the sounds, therefore here is the brief introduction about the characteristics of sound: Sound has two physical (frequency, intensity noise) and psychological (pitch, loudness) factors. These two factors are equivalent. This means that when we speak the intonation of the voice is the same as Sound intensity. The human ear is structured in such a way that if the intensity remains stable but the frequency changes, one feels that the volume has changed while it is not. Noise can be classified in three cases: pure melody, melody and noise. In architecture, one purpose is to control noise. To control the noise first we must measure the volume of noise. Humans can hear I40 dB at the maximum level. If noise level gets greater than I40 dB, the human eardrum will be ruptured. The sound of silence is below 40 dB. Acoustic science is important although there are just a few projects and papers presented about this subject. Many students are unfamiliar with this topic and designer might not notice to this matter. Therefore, an article that includes a simple method for acoustic status check is necessary. Some researches have done on the harmful effects of noise pollution on humans (Movafagh, 2009; Hedayati.I994). In this articles background noise has been obtained in some examples such as Alghadir hospital and Ecbatan apartments by using Sound meter. Then some strategies for reducing noise pollution will be expressed. This paper is done for complete the process of previous projects. In this paper, the sample is selected among common apartment because Acoustic comfort in the building should be considered for all construction. This is particularly important in buildings bordering the highway. The acoustics of the building should consider the following terms: I. Noise Criterion 2. Sound Rated Walls 3. Silent Installation Systems 4. Building Form 5. Sound Level. Noise criterion for buildings with different user codes is in section I8 of the national regulations. Regarding to the external environment, including voice traffic noise, sounds of the space must be well control. This is especially important in the halls or conference halls and cinemas. For this purpose, we first calculated the amount of background noise and the sound reduction index for façade and then the amount of noise in the unit. Using the guidelines, the volume was brought to an optimal level and comparison of the performance is done. In this paper, the effect of echoed in the interior of the apartment was not evaluated. The results show that in the three mentioned cases, the best method is to use double- glazed windows. This method can be used indoors to create the desired sound level. Using simple windows and double walls had minimum impact. In this case, the noise reduction was about 20 dB. This amount is very low. We will have a better effect when we use double glazed windows and double walls together. Due to the high costs that this method, by using only the double window, we can reach the level desired. Therefore, the proposed solution is use of the double glazed windows. At the end, with a proper design and use of appropriate materials, we can create sound insulation against noise. Studying on samples, wall modification will improve voice. [ABSTRACT FROM AUTHOR]

Background and Objective: Parkinson's Disease (PD) is a progressive disease resulting from a reduction in the release of dopamine. This loss of dopamine can have an effect on non- speech movements, as well as various aspects of speech production. Dysarthria is a collective name for a group of speech disorders resulting from disturbance in muscular control over the speech mechanism due to damage to the central or peripheral nervous system. It produces problems in oral communication due to paralysis, weakness or incoordination of the speech musculature. A synthesis of research on normal and neurologically disordered speech should lead to an improved understanding of the neural regulation of speech. Subjects and Methods: In this cross-sectional study, 36 voice samples in normal voiceless environment were recorded. Frequency difference in high and low vowels was measured by Praat software. Data analysis was performed by Independent Samples Test and Maan-Whiteny tests. Results: All variables showed significant differences.F1-F0 in low vowels were significantly decreased in adults with Parkinson (P< 0.001). F2-F1 in high vowels was significantly decreased in adults with Parkinson (P < 0.05). Conclusion: The results showed that Parkinson disease affects formant frequency. [ABSTRACT FROM AUTHOR]