Displaying publications 1 - 20 of 89 in total

Abstract:
Sort:
  1. Huang ZL, Wang DY, Zhang PC, Dong F, Yeoh KH
    Acta Otolaryngol, 2001 Oct;121(7):844-8.
    PMID: 11718250
    Acoustic rhinometry (AR) evaluates the geometry of the nasal cavity by measuring the minimum cross-sectional area (MCA) and nasal volume (V) by means of acoustic reflection. Understanding the normal and pathologic conditions of the internal nasal cavity using AR is important in the diagnosis of structural abnormalities in patients. The aim of this study was to investigate the normal range of AR parameters in healthy volunteers from three ethnic groups in Singapore: Chinese, Malay and Indian. We also attempted to evaluate the role of these measurements in the documentation of structural abnormalities in the nose. A total of 189 Singaporeans, aged > or = 18 years, were recruited from a nationwide survey study. They comprised 83 Chinese, 35 Malays and 71 Indians. Eighty-nine subjects had a rhinoscopically normal nose (Group 1), 77 had significant septal deviation (Group 2) and 23 had inferior turbinate hypertrophy (Group 3). AR was performed to measure the MCA at the anterior 1-5 cm from the nostril and the volume (V) between points at the nostril and 5 cm into the nose. A mean MCA (mMCA; equal to (L + R)/2) and a total volume (Vt; equal to L + R) were then calculated for each subject, where L and R refer to the measurements made for the left and right nostrils, respectively. The results showed that there was no statistically significant difference in mMCA (p = 0.80) and Vt (p = 0.60) among the three ethnic subgroups of Group 1. Statistically significant differences were found only between Groups 1 and 3 (p < 0.001 for both mMCA and Vt) and between Groups 2 and 3 (p = 0.001 for mMCA and p = 0.013 for Vt). Although there was no significant difference between Groups 1 and 2, significant differences in MCA (p = 0.001) and V (p = 0.040) were found between the narrower sides (smaller volume) and the wider sides in Group 2, indicating volume compensation between the nasal cavities. In conclusion, our study demonstrates that there is no significant difference in the normal range of AR measurements among Chinese, Malay and Indian ethnic groups. AR is able to determine the structural abnormality of the internal nasal cavity caused by septal deviation and inferior turbinate hypertrophy.
    Matched MeSH terms: Acoustics
  2. Johari SF, Azman M, Mohamed AS, Baki MM
    J Laryngol Otol, 2020 Dec;134(12):1085-1093.
    PMID: 33308327 DOI: 10.1017/S0022215120002558
    OBJECTIVE: To evaluate voice intensity as the primary outcome measurement when treating unilateral vocal fold paralysis patients.

    METHODS: This prospective observational study comprised 34 newly diagnosed unilateral vocal fold paralysis patients undergoing surgical interventions: injection laryngoplasty or medialisation thyroplasty. Voice assessments, including maximum vocal intensity and other acoustic parameters, were performed at baseline and at one and three months post-intervention. Maximum vocal intensity was also repeated within two weeks before any surgical interventions were performed. The results were compared between different time points and between the two intervention groups.

    RESULTS: Maximum vocal intensity showed high internal consistency. Statistically significant improvements were seen in maximum vocal intensity, Voice Handicap Index-10 and other acoustic analyses at one and three months post-intervention. A significant moderate negative correlation was demonstrated between maximum vocal intensity and Voice Handicap Index-10, shimmer and jitter. There were no significant differences in voice outcomes between injection laryngoplasty and medialisation thyroplasty patients at any time point.

    CONCLUSION: Maximum vocal intensity can be applied as a treatment outcome measure in unilateral vocal fold paralysis patients; it can demonstrate the effectiveness of treatment and moderately correlates with self-reported outcome measures.

    Matched MeSH terms: Speech Acoustics
  3. Abdelatti ZAS, Hartbauer M
    Hear Res, 2017 11;355:70-80.
    PMID: 28974384 DOI: 10.1016/j.heares.2017.09.011
    In forest clearings of the Malaysian rainforest, chirping and trilling Mecopoda species often live in sympatry. We investigated whether a phenomenon known as stochastic resonance (SR) improved the ability of individuals to detect a low-frequent signal component typical of chirps when members of the heterospecific trilling species were simultaneously active. This phenomenon may explain the fact that the chirping species upholds entrainment to the conspecific song in the presence of the trill. Therefore, we evaluated the response probability of an ascending auditory neuron (TN-1) in individuals of the chirping Mecopoda species to triple-pulsed 2, 8 and 20 kHz signals that were broadcast 1 dB below the hearing threshold while increasing the intensity of either white noise or a typical triller song. Our results demonstrate the existence of SR over a rather broad range of signal-to-noise ratios (SNRs) of input signals when periodic 2 kHz and 20 kHz signals were presented at the same time as white noise. Using the chirp-specific 2 kHz signal as a stimulus, the maximum TN-1 response probability frequently exceeded the 50% threshold if the trill was broadcast simultaneously. Playback of an 8 kHz signal, a common frequency band component of the trill, yielded a similar result. Nevertheless, using the trill as a masker, the signal-related TN-1 spiking probability was rather variable. The variability on an individual level resulted from correlations between the phase relationship of the signal and syllables of the trill. For the first time, these results demonstrate the existence of SR in acoustically-communicating insects and suggest that the calling song of heterospecifics may facilitate the detection of a subthreshold signal component in certain situations. The results of the simulation of sound propagation in a computer model suggest a wide range of sender-receiver distances in which the triller can help to improve the detection of subthreshold signals in the chirping species.
    Matched MeSH terms: Acoustics
  4. Dabbagh A, Abdullah BJ, Abu Kasim NH, Ramasindarum C
    Int J Hyperthermia, 2014 Feb;30(1):66-74.
    PMID: 24286257 DOI: 10.3109/02656736.2013.854930
    The emergence of thermal modalities has promoted the use of heat-sensitive phantoms for calibration, measurement, and verification purposes. However, development of durable phantoms with high precision ability to represent the temperature distribution remains a challenge. This study aims to introduce a reusable phantom that provides an accurate assessment of the heated region in various thermal modalities.
    Matched MeSH terms: Acoustics
  5. Lai YH
    J Psycholinguist Res, 2012 Aug;41(4):237-52.
    PMID: 22089521 DOI: 10.1007/s10936-011-9190-2
    Nasals are cross-linguistically susceptible to change, especially in the syllable final position. Acoustic reports on Mandarin nasal production have recently shown that the syllable-final distinction is frequently dropped. Few studies, however, have addressed the issue of perceptual processing in Mandarin nasals for L1 and L2 speakers of Mandarin Chinese. The current paper addressed to what extent and in what directions L1 and L2 speakers of Mandarin differed in perceiving Mandarin nasals. Possible variables, including the linguistic backgrounds (i.e. L1 vs. L2 speakers of Mandarin Chinese), the vocalic contexts (i.e. [i, ə, a, y, ua, uə, ia]) and the phonetic settings (i.e. syllable-initial vs. syllable-final), were discussed. Asymmetrical findings in the current investigation indicated limitations of speech learning theories developed from European languages in the context of Mandarin nasals. A tri-dimensional model was thus suggested for interpreting the cognitive mechanism in Mandarin nasal perception.
    Matched MeSH terms: Speech Acoustics
  6. Ting CM, Samdin SB, Salleh ShH, Omar MH, Kamarulafizam I
    PMID: 23367426 DOI: 10.1109/EMBC.2012.6347491
    This paper applies an expectation-maximization (EM) based Kalman smoother (KS) approach for single-trial event-related potential (ERP) estimation. Existing studies assume a Markov diffusion process for the dynamics of ERP parameters which is recursively estimated by optimal filtering approaches such as Kalman filter (KF). However, these studies only consider estimation of ERP state parameters while the model parameters are pre-specified using manual tuning, which is time-consuming for practical usage besides giving suboptimal estimates. We extend the KF approach by adding EM based maximum likelihood estimation of the model parameters to obtain more accurate ERP estimates automatically. We also introduce different model variants by allowing flexibility in the covariance structure of model noises. Optimal model selection is performed based on Akaike Information Criterion (AIC). The method is applied to estimation of chirp-evoked auditory brainstem responses (ABRs) for detection of wave V critical for assessment of hearing loss. Results shows that use of more complex covariances are better estimating inter-trial variability.
    Matched MeSH terms: Acoustics
  7. Panda D, Manickam S
    Ultrason Sonochem, 2019 Mar;51:526-532.
    PMID: 30224289 DOI: 10.1016/j.ultsonch.2018.04.003
    Dicofol, a recommended Stockholm convention persistent organic pollutants (POPs) candidate is well known for its endocrine disruptive properties and has been extensively used as an organochlorine pesticide worldwide. The hydrodynamic cavitation (HC) treatment of Dicofol in aqueous media induced by a liquid whistle hydrodynamic cavitaion reactor (LWHCR) has been investigated while considering important parameters such as inlet pressure, initial concentration of Dicofol, solution temperature, pH, addition of H2O2 and radical scavenger for the extent of degradation. The pseudo-first-order degradation rate constant (k) was determined to be 0.073 min-1 with a cavitational yield of 1.26 × 10-5 mg/J at optimum operating conditions and a complete removal of Dicofol was achieved within 1 h of treatment. Considering the removal rate and energy efficiency, the optimal inlet pressure was found to be 7 bar, resulting in a cavitation number of 0.17. High performance liquid chromatography (HPLC) and Gas chromatography mass spectroscopy (GC-MS) analyses indicated a sharp decline in the concentration of Dicofol with treatment time and indicated the presence of degraded products. An 85% total organic carbon (TOC) removal was achieved within 1 h of treatment time, demonstrating successful mineralization of Dicofol. The obtained results suggest that the degradation of Dicofol followed thermal decomposition and successive recombination reactions at bubble-vapor interface. Overall, the attempted hydrodynamic cavitation demonstrated successful and rapid removal of endocrine disruptive chemicals such as Dicofol and is expected to provide efficient solution for wastewater treatment.
    Matched MeSH terms: Acoustics
  8. Wahab NA, Rashid MF
    Singapore Med J, 2009 Nov;50(11):1077-9.
    PMID: 19960163
    INTRODUCTION: The present study aimed to obtain preliminary tympanometric data of young Malay adults and to compare the results between genders.
    METHODS: 96 undergraduate students (49 males and 47 females), aged 19-25 (mean and standard deviation 21.14 +/- 1.31) years, participated in this study. Otoscopic examination, pure tone audiometry, qualitative tympanogram and ipsilateral acoustic reflex were measured to ensure a clear ear canal, normal hearing and normal middle ear function, prior to tympanometric measurement. As a result, a total of 154 ears (80 ears from males and 74 ears from females) were selected for further statistical analyses. The tympanometric parameters measured were peak compensated static acoustic admittance (Peak Y(tm)), tympanometric width (TW) and equivalent ear canal volume (V(ea)).
    RESULTS: The results showed that the mean Peak Y(tm), V(ea) and TW for males were 0.81 mmhos, 1.48 cubic cm and 113.67 daPa, respectively. The mean Peak Y(tm), V(ea) and TW for females were 0.63 mmhos, 1.12 cubic cm and 98.04 daPa, respectively. Males were found to have significantly higher mean V(ea) and mean Peak Y(tm) than females. However no significant gender difference was observed in the mean TW.
    CONCLUSION: The current study suggests that young Malay adults may require gender-specific Peak Y(tm) and V(ea) values when implementing a quantitative approach in tympanogram interpretation.
    Matched MeSH terms: Acoustics
  9. Ooi CC, Wong AM
    Int J Speech Lang Pathol, 2012 Dec;14(6):499-508.
    PMID: 23039126 DOI: 10.3109/17549507.2012.712159
    One reason why specific language impairment (SLI) is grossly under-identified in Malaysia is the absence of locally- developed norm-referenced language assessment tools for its multilingual and multicultural population. Spontaneous language samples provide quantitative information for language assessment, and useful descriptive information on child language development in complex language and cultural environments. This research consisted of two studies and investigated the use of measures obtained from English conversational samples among bilingual Chinese-English Malaysian preschoolers. The research found that the language sample measures were sensitive to developmental changes in this population and could identify SLI. The first study examined the relationship between age and mean length of utterance (MLU(w)), lexical diversity (D), and the index of productive syntax (IPSyn) among 52 typically-developing (TD) children aged between 3;4-6;9. Analyses showed a significant linear relationship between age and D (r = .450), the IPsyn (r = .441), and MLU(w) (r = .318). The second study compared the same measures obtained from 10 children with SLI, aged between 3;8-5;11, and their age-matched controls. The children with SLI had significantly shorter MLU(w) and lower IPSyn scores than the TD children. These findings suggest that utterance length and syntax production can be potential clinical markers of SLI in Chinese-English Malaysian children.
    Matched MeSH terms: Speech Acoustics*
  10. Chu SY, Barlow SM, Lee J, Wang J
    Int J Speech Lang Pathol, 2017 12;19(6):616-627.
    PMID: 28425760 DOI: 10.1080/17549507.2016.1265587
    PURPOSE: This research characterised perioral muscle reciprocity and amplitude ratio in lower lip during bilabial syllable production [pa] at three rates to understand the neuromotor dynamics and scaling of motor speech patterns in individuals with Parkinson's disease (PD).

    METHOD: Electromyographic (EMG) signals of the orbicularis oris superior [OOS], orbicularis oris inferior [OOI] and depressor labii inferioris [DLI] were recorded during syllable production and expressed as polar-phase notations.

    RESULT: PD participants exhibited the general features of reciprocity between OOS, OOI and DLI muscles as reflected in the EMG during syllable production. The control group showed significantly higher integrated EMG amplitude ratio in the DLI:OOS muscle pairs than PD participants. No speech rate effects were found in EMG muscle reciprocity and amplitude magnitude across all muscle pairs.

    CONCLUSION: Similar patterns of muscle reciprocity in PD and controls suggest that corticomotoneuronal output to the facial nucleus and respective perioral muscles is relatively well-preserved in our cohort of mild idiopathic PD participants. Reduction of EMG amplitude ratio among PD participants is consistent with the putative reduction in the thalamocortical activation characteristic of this disease which limits motor cortex drive from generating appropriate commands which contributes to bradykinesia and hypokinesia of the orofacial mechanism.

    Matched MeSH terms: Speech Acoustics*
  11. Phoon HS, Abdullah AC, Maclagan M
    Int J Speech Lang Pathol, 2012 Dec;14(6):487-98.
    PMID: 23039125 DOI: 10.3109/17549507.2012.719549
    This study investigates the effect of dialect on phonological analyses in Chinese-influenced Malaysian English (ChME) speaking children. A total of 264 typically-developing ChME speaking children aged 3-7 years participated in this cross-sectional study. A single word naming task consisting of 195 words was used to elicit speech from the children. The samples obtained were transcribed phonetically and analysed descriptively and statistically. Phonological analyses were completed for speech sound accuracy, age of consonant acquisition, percentage of phonological process occurrence, and age of suppression for phonological processes. All these measurements differed based on whether or not ChME dialectal features were considered correct, with children gaining higher scores when ChME dialect features were considered correct. The findings of the present study provide guidelines for Malaysian speech-language pathologists and stress the need to appropriately consider ChME dialectal features in the phonological analysis of ChME speaking children. They also highlight the issues in accurate differential diagnosis of speech impairment for speech-language pathologists working with children from any linguistically diverse background.
    Matched MeSH terms: Speech Acoustics*
  12. Ali Z, Alsulaiman M, Muhammad G, Elamvazuthi I, Al-Nasheri A, Mesallam TA, et al.
    J Voice, 2017 May;31(3):386.e1-386.e8.
    PMID: 27745756 DOI: 10.1016/j.jvoice.2016.09.009
    A large population around the world has voice complications. Various approaches for subjective and objective evaluations have been suggested in the literature. The subjective approach strongly depends on the experience and area of expertise of a clinician, and human error cannot be neglected. On the other hand, the objective or automatic approach is noninvasive. Automatic developed systems can provide complementary information that may be helpful for a clinician in the early screening of a voice disorder. At the same time, automatic systems can be deployed in remote areas where a general practitioner can use them and may refer the patient to a specialist to avoid complications that may be life threatening. Many automatic systems for disorder detection have been developed by applying different types of conventional speech features such as the linear prediction coefficients, linear prediction cepstral coefficients, and Mel-frequency cepstral coefficients (MFCCs). This study aims to ascertain whether conventional speech features detect voice pathology reliably, and whether they can be correlated with voice quality. To investigate this, an automatic detection system based on MFCC was developed, and three different voice disorder databases were used in this study. The experimental results suggest that the accuracy of the MFCC-based system varies from database to database. The detection rate for the intra-database ranges from 72% to 95%, and that for the inter-database is from 47% to 82%. The results conclude that conventional speech features are not correlated with voice, and hence are not reliable in pathology detection.
    Matched MeSH terms: Speech Acoustics*
  13. Lim AC, Chong VC, Wong CS, Muniandy SV
    PeerJ, 2015;3:e1471.
    PMID: 26734507 DOI: 10.7717/peerj.1471
    Background. Syngnathid fishes produce three kinds of sounds, named click, growl and purr. These sounds are generated by different mechanisms to give a consistent signal pattern or signature which is believed to play a role in intraspecific and interspecific communication. Commonly known sounds are produced when the fish feeds (click, purr) or is under duress (growl). While there are more acoustic studies on seahorses, pipefishes have not received much attention. Here we document the differences in feeding click signals between three species of pipefishes and relate them to cranial morphology and kinesis, or the sound-producing mechanism. Methods. The feeding clicks of two species of freshwater pipefishes, Doryichthys martensii and Doryichthys deokhathoides and one species of estuarine pipefish, Syngnathoides biaculeatus, were recorded by a hydrophone in acoustic dampened tanks. The acoustic signals were analysed using time-scale distribution (or scalogram) based on wavelet transform. A detailed time-varying analysis of the spectral contents of the localized acoustic signal was obtained by jointly interpreting the oscillogram, scalogram and power spectrum. The heads of both Doryichthys species were prepared for microtomographical scans which were analysed using a 3D imaging software. Additionally, the cranial bones of all three species were examined using a clearing and double-staining method for histological studies. Results. The sound characteristics of the feeding click of the pipefish is species-specific, appearing to be dependent on three bones: the supraoccipital, 1st postcranial plate and 2nd postcranial plate. The sounds are generated when the head of the Dorichthyes pipefishes flexes backward during the feeding strike, as the supraoccipital slides backwards, striking and pushing the 1st postcranial plate against (and striking) the 2nd postcranial plate. In the Syngnathoides pipefish, in the absence of the 1st postcranial plate, the supraoccipital rubs against the 2nd postcranial plate twice as it is pulled backward and released on the return. Cranial morphology and kinesis produce acoustic signals consistent with the bone strikes that produce sharp energy spikes (discrete or merged), or stridulations between bones that produce repeated or multimodal sinusoidal waveforms. Discussion. The variable structure of the sound-producing mechanism explains the unique acoustic signatures of the three species of pipefish. The differences in cranial bone morphology, cranial kinesis and acoustic signatures among pipefishes (and seahorses) could be attributed to independent evolution within the Syngnathidae, which warrants further investigation.
    Matched MeSH terms: Acoustics
  14. Dabbagh A, Abdullah BJ, Ramasindarum C, Abu Kasim NH
    Ultrason Imaging, 2014 Oct;36(4):291-316.
    PMID: 24626566 DOI: 10.1177/0161734614526372
    Tissue-mimicking phantoms that are currently available for routine biomedical applications may not be suitable for high-temperature experiments or calibration of thermal modalities. Therefore, design and fabrication of customized thermal phantoms with tailored properties are necessary for thermal therapy studies. A multitude of thermal phantoms have been developed in liquid, solid, and gel forms to simulate biological tissues in thermal therapy experiments. This article is an attempt to outline the various materials and techniques used to prepare thermal phantoms in the gel state. The relevant thermal, electrical, acoustic, and optical properties of these phantoms are presented in detail and the benefits and shortcomings of each type are discussed. This review could assist the researchers in the selection of appropriate phantom recipes for their in vitro study of thermal modalities and highlight the limitations of current phantom recipes that remain to be addressed in further studies.
    Matched MeSH terms: Acoustics
  15. Mustafa MB, Salim SS, Mohamed N, Al-Qatab B, Siong CE
    PLoS One, 2014;9(1):e86285.
    PMID: 24466004 DOI: 10.1371/journal.pone.0086285
    Automatic speech recognition (ASR) is currently used in many assistive technologies, such as helping individuals with speech impairment in their communication ability. One challenge in ASR for speech-impaired individuals is the difficulty in obtaining a good speech database of impaired speakers for building an effective speech acoustic model. Because there are very few existing databases of impaired speech, which are also limited in size, the obvious solution to build a speech acoustic model of impaired speech is by employing adaptation techniques. However, issues that have not been addressed in existing studies in the area of adaptation for speech impairment are as follows: (1) identifying the most effective adaptation technique for impaired speech; and (2) the use of suitable source models to build an effective impaired-speech acoustic model. This research investigates the above-mentioned two issues on dysarthria, a type of speech impairment affecting millions of people. We applied both unimpaired and impaired speech as the source model with well-known adaptation techniques like the maximum likelihood linear regression (MLLR) and the constrained-MLLR(C-MLLR). The recognition accuracy of each impaired speech acoustic model is measured in terms of word error rate (WER), with further assessments, including phoneme insertion, substitution and deletion rates. Unimpaired speech when combined with limited high-quality speech-impaired data improves performance of ASR systems in recognising severely impaired dysarthric speech. The C-MLLR adaptation technique was also found to be better than MLLR in recognising mildly and moderately impaired speech based on the statistical analysis of the WER. It was found that phoneme substitution was the biggest contributing factor in WER in dysarthric speech for all levels of severity. The results show that the speech acoustic models derived from suitable adaptation techniques improve the performance of ASR systems in recognising impaired speech with limited adaptation data.
    Matched MeSH terms: Speech Acoustics
  16. Al-Yahya SN, Muhammad R, Suhaimi SNA, Azman M, Mohamed AS, Baki MM
    J Voice, 2020 Sep;34(5):811.e13-811.e20.
    PMID: 30612893 DOI: 10.1016/j.jvoice.2018.12.003
    OBJECTIVES: Selective laryngeal examination for patients undergoing thyroidectomy is recommended for patients with voice alterations, history of prior cervical or chest surgery, and patients with proven or suspected thyroid malignancy. The study objective is to measure the sensitivity of surgeons in detecting voice abnormalities in patients undergoing thyroidectomy, parathyroidectomy complicated with laryngeal nerve paralysis, or patients with known vocal cords palsy (VCP) due to other neck surgeries.

    DESIGN AND SETTING: Descriptive cross-sectional study in a tertiary center.

    PARTICIPANTS AND METHODS: The subjects are 274 audio files of voices of patients undergoing thyroid, parathyroid surgeries, and known VCP due to other neck surgeries. Voice assessments were done by three endocrine surgeons (A, B, and C) with 20, 12, and 4 years of surgical experience.

    MAIN OUTCOME MEASURES: Sensitivity and specificity of surgeon documented voice assessment in patients with underlying VCP. Subjects' acoustic analysis and Voice Handicap Index (VHI-10) were analyzed.

    RESULTS: Raters A, B, and C have sensitivity of 63.6%, 78.8%, and 66.7%, respectively. Inter-rater reliability shows substantial agreement (ƙ = 0.67). VHI-10 has sensitivity of 75.8% and strong correlation of 0.707 (p value <0.001) to VCP. Subjects with VCP have notably higher jitter, shimmer, and noise-to-harmonic ratio compared to normal subjects with sensitivity of 74.2%, 71.2%, and 72.7%, respectively.

    CONCLUSIONS: The results for surgeons documented voice assessment did not reach the desired sensitivity for a screening tool for patients with underlying VCP. Other tools such as VHI-10 and acoustic analysis may not be used as standalone tools in screening patients with underlying VCP. Routine preoperative laryngeal examination may be recommended for all patients undergoing thyroid, parathyroid, or other surgeries that places the laryngeal nerves at risk.

    Matched MeSH terms: Acoustics
  17. Umi Nadrah Amran, Farah Wahida Ahmad Zaiki
    MyJurnal
    Introduction: Doppler mode ultrasound is widely used in prenatal scanning and known to produce a higher acoustic
    output which later leads to higher heat energy conversion compared to other ultrasound modes. It has been reported
    that the use of Doppler imaging might increase the temperature of tissues, thus, when Doppler is used in combination with 2D ultrasound, the risks of bioeffects tend to increase more. It is also known that prolonged exposure to
    ultrasound during pregnancy can cause irreversible biological destructions to the fetus. Despite the benefits of using
    Doppler ultrasound, its potential adverse effects have received scant attention in the research literature. Therefore,
    this study aimed to examine a correlation between gestational stages (GS) and newborn rabbit’s body weight at different prenatal Doppler ultrasound exposure durations. Methods: Twelve pregnant New Zealand white rabbits (NZWR)
    were exposed once using three different Doppler ultrasound exposure durations (30, 60, 90 minutes exposure) at
    three different GSs (1st, 2nd, and 3rd GS). After delivery, the mean weights of the 62 newborns were statistically analysed. Results: Strong negative and positive correlation between newborn’s body weight at different GSs and Doppler
    ultrasound exposure durations with a significant result found in 60 minutes exposure (p =
    Matched MeSH terms: Acoustics
  18. Alabduljabbar H, Huseien GF, Sam ARM, Alyouef R, Algaifi HA, Alaskar A
    Materials (Basel), 2020 Dec 02;13(23).
    PMID: 33276508 DOI: 10.3390/ma13235490
    Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.
    Matched MeSH terms: Acoustics
  19. Palaniappan R, Sundaraj K, Sundaraj S
    Comput Methods Programs Biomed, 2017 Jul;145:67-72.
    PMID: 28552127 DOI: 10.1016/j.cmpb.2017.04.013
    BACKGROUND: The monitoring of the respiratory rate is vital in several medical conditions, including sleep apnea because patients with sleep apnea exhibit an irregular respiratory rate compared with controls. Therefore, monitoring the respiratory rate by detecting the different breath phases is crucial.

    OBJECTIVES: This study aimed to segment the breath cycles from pulmonary acoustic signals using the newly developed adaptive neuro-fuzzy inference system (ANFIS) based on breath phase detection and to subsequently evaluate the performance of the system.

    METHODS: The normalised averaged power spectral density for each segment was fuzzified, and a set of fuzzy rules was formulated. The ANFIS was developed to detect the breath phases and subsequently perform breath cycle segmentation. To evaluate the performance of the proposed method, the root mean square error (RMSE) and correlation coefficient values were calculated and analysed, and the proposed method was then validated using data collected at KIMS Hospital and the RALE standard dataset.

    RESULTS: The analysis of the correlation coefficient of the neuro-fuzzy model, which was performed to evaluate its performance, revealed a correlation strength of r = 0.9925, and the RMSE for the neuro-fuzzy model was found to equal 0.0069.

    CONCLUSION: The proposed neuro-fuzzy model performs better than the fuzzy inference system (FIS) in detecting the breath phases and segmenting the breath cycles and requires less rules than FIS.

    Matched MeSH terms: Acoustics
  20. Mat-Shayuti MS, Tuan Ya TMYS, Abdullah MZ, Megat Khamaruddin PNF, Othman NH
    Environ Sci Pollut Res Int, 2019 Sep;26(26):26419-26438.
    PMID: 31327143 DOI: 10.1007/s11356-019-05954-w
    Steady efforts in using ultrasonic energy to treat oil-contaminated sand started in the early 2000s until today, although pilot studies on the area can be traced to even earlier dates. Owing to the unique characteristics of the acoustic means, the separation of oil from sand has been showing good results in laboratories. This review provides the compilation of researches and insights into the mechanism of separation thus far. Related topics in the areas of oil-contaminated sand characterizations, fundamental ultrasonic cleaning, and cavitation effects are also addressed. Nevertheless, many of the documented works are only at laboratory or pilot-scale level, and the comprehensive interaction between ultrasonic parameters towards cleaning efficiencies may not have been fully unveiled. Gaps and opportunities are also presented at the end of this article.
    Matched MeSH terms: Acoustics
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links