bluuebunny/crossref_metadata_2025 huggingface dataset:
Ex vivo study of vagal branches at risk for iatrogenic injury during laryngoplasty in horses
Authors: Pisano Simone R. R. , Stoffel Michael H. , Bodó Gábor
Published: December 2020

Objective

To localize vagal branches within the surgical field of laryngoplasty and identify potentially hazardous surgical steps.

Study design

Observational cadaveric study.

Sample population

Five equine head–neck specimens and four entire equine cadavers.

Methods

Dissection of the pharyngeal region from a surgical perspective. Neuronal structures were considered at risk if touched or if the distance to instruments was less than 5 mm.

Results

The branches of the pharyngeal plexus (PP) supplying the cricopharyngeal muscle (PPcr), the thyropharyngeal muscle (PPth), and the esophagus (PPes) were identified in the surgical field in nine of nine, five of nine, and one of nine specimens, respectively. The internal branch of the cranial laryngeal nerve (ibCLN) was identified within the carotid sheath in six of nine specimens. The external branch of the cranial laryngeal nerve (ebCLN) was identified close to the septum of the caudal constrictors in nine of nine specimens.

The blade of the tissue retractor compressed the ibCLN in six of six, the ebCLN in four of six, the PPcr in six of six, the PPth in two of three, and the PPes in two of two specimens in which the respective nerves were identified after further dissection. Surgical exploration of the dorsolateral aspect of the pharynx and the incision of the septum of the caudal constrictors harmed the ebCLN in nine of nine, PPcr in seven of nine, and PPth in four of eight specimens.

Conclusion

Several vagal branches were located in the surgical field and must be considered at risk because of their location.

Clinical significance

Use of the tissue retractor, dissection over the pharynx, and dissection of the septum of the caudal constrictors involve a risk to damage vagal branches.
Significance of the Direct Excitation Mechanism for High-Frequency Response of Premixed Flames to Flow Oscillations
Authors: Acharya Vishal S. , Lieuwen Timothy C.
Published: December 2020

Premixed flames are sensitive to flow disturbances, which can arise from acoustic or vortical fluctuations. For transverse instabilities, it is known that a dominant mechanism for flame response is “injector coupling,” whereby pressure oscillations associated with transverse waves excite axial flow disturbances. These axial flow disturbances then excite heat release oscillations. The objective of this paper is to consider another mechanism—the direct sensitivity of the unsteady heat release to transverse acoustic waves—and to compare its significance relative to the induced axial disturbances, in a linear framework. The rate at which the flame adds energy to the disturbance field is quantified using the Rayleigh criterion and evaluated over a range of control parameters, such as flame length and swirl number. The results show that radial modes induce heat release fluctuations that always add energy to the acoustic field, whereas heat release fluctuations induced by mixed radial-azimuthal modes can add or remove energy. These amplification rates are then compared to the flame response from induced axial fluctuations. For combustor-centered flames, these results show that the direct excitation mechanism has negligible amplification rates relative to the induced axial mechanism for radial modes. For transverse modes, the fact that the nozzle is located at a pressure node indicates that negligible induced axial velocity disturbances are excited; as such, the direct mechanism dominates. For flames that are not centered on pressure nodes, the direct mechanism for mixed modes dominates for certain nozzle locations and flame angles.
Region-Based Efficient Computer Numerical Control Machining Using Point Cloud Data
Authors: Dhanda Mandeep , Kukreja Aman , Pande S. S.
Published: December 2020

This paper presents an efficient tool path planning strategy for three-axis computer numeric control (CNC) machining using curvature-based segmentation (CBS) of freeform surface from its representation in the form of a point cloud. Curvature parameters estimated over the point data are used to partition the surface into convex, concave, and saddle-like regions. Grid-based adaptive planar tool path planning strategy is developed to machine each region separately within its boundaries. In addition to the region-by-region machining, a strategy to stitch the obtained regions is also developed to minimize the tool lifts and tool marks. The developed region-based tool path planning strategy is compared with the point-cloud-based adaptive planar strategy, iso-scallop strategy, and commercial software for parts with various complexities. The result shows significant improvement in terms of performance parameters, namely, machining time, tool path length, and code length while maintaining the desired part surface quality. The proposed method is also tested by machining a real surface and analyzing its surface quality.
Dynamic Stability of Sandwich Beams/Wide Plates Subjected to Axial Impulsive Loads
Authors: Yuan Zhangxian , Kardomateas George A.
Published: December 2020

This paper presents an analysis for the dynamic stability of sandwich beams/wide plates subjected to axial impulsive loads. The formulation and solution of the problem is done by use of the extended high-order sandwich panel theory (EHSAPT). With the initial geometric imperfection included, the equations of motion in terms of seven generalized displacements are derived. The dynamic response of sandwich panels subjected to three different types of impulsive loads, namely, step, linear decay, and triangular impulse, is studied. Furthermore, the effects of the oscillation mode number, face/core materials, and geometries are investigated. It is observed that all measurements of the dynamic response, such as the maximum displacements, strains, and stresses, change at the same rate as the change of the impulse load magnitude and duration, for a specific impulse load profile. When the impulse load is lower than the static buckling load, the dynamic response is bounded no matter how long the load is applied. A step impulsive axial load with magnitude lower than the static buckling load can lead a sandwich panel to have a dynamic response as high as twice the static response. When the impulse load is higher than the static critical load, the dynamic response is unbounded with increasing load duration. However, it is possible that the dynamic response can be controlled at a low level if the duration of the impulse load is short enough, and thus, in this case, the load can safely exceed the static critical load.
Fatigue Benchmark Comparison Effort Between Code_Aster and CNNC/NPIC Software: Part 2
Authors: Xie Hai , Kong Zichen , Shao Xuejiao , Mathieu Tanguy , Xiong Furui
Published: December 2020

Fatigue is identified as a significant degradation mode that affects nuclear power plants world-wide. Recent research on the interaction between fatigue degradation and the influence of PWR environment has caused international concern and triggered numerous research programs [1]. In this context, several codes & standards, including the RCC-M code, have included some technical mandatory or non-mandatory sections to address the issue. In RCC-M, this is compiled in the Rules in Probation Phase 2 and 3 [2].

Due to the novelty of these rules, there is room for improvement for the specific and practical implementation of these rules. AFCEN has hence launched a benchmark exercise at the end of 2019 to help increase the quality of these rules.

Part 1 of this paper [3] states that EDF and CNNC/NPIC have launched an effort to benchmark their respective codes on fatigue calculation including the EAF algorithm. In the second part of the benchmark, the two companies started the code comparison based on a benchmark case provided by AFCEN.

As stated previously, the 2016 edition of RCC-M code integrates the modifications made to the Code in Probation Phase 2 and 3(RPP)[2], which respectively modify the fatigue design curve for austenitic stainless steels and Nickel base alloys, as well as integrate environmental effects in the fatigue evaluation for austenitic stainless steel components. In this paper, a comparison between RCC-M RPP and NUREG/CR-6909 rev.1 [3] is proposed. The comparison focuses on the technical details of the strain rate calculation and transient combination method.

The cumulative fatigue usage factor with or without considering EAF according to RCC-M RPP – 2 and RPP – 3 is given by EDF, using code_aster and its POST_RCCM operator. CNNC/NPIC will provide multiple sets of results including cumulative fatigue usage factors according to RCC-M RPP and NUREG CR/6909 rev. 1 respectively using its own software. Comparison of selection for peak and valleys points, Sn and Fen values are also presented. Differences of the algorithms of the two codes are also discussed.
Research on Regulations and Standards for Inspection of Atmospheric Liquid Metal Tank Trucks for Hazardous Chemicals
Authors: Fang Zhou , Wang Zhe , Li Guanghai
Published: December 2020

Atmospheric tank truck is a dangerous chemical road transport tool widely used in petroleum and petrochemical industries. The quality and safety of tank truck are closely related to people’s life and property safety. Through investigation and study, the biggest problem of atmospheric tank truck safety system is that the level of regular inspection, safety accessories selection and inspection, inspection organization qualification, safety assessment and other aspects are inadequate, and there is no specific basis for actual operation. Chinese Relevant regulations and standards are summarized and compared, and the gap between the existing basis for inspection and evaluation and the actual operation needs are put forward, aiming at above key issues. The existing problems and their causes in the field of road transportation of dangerous chemical atmospheric tank trucks are studied, including the ex-factory inspection, in-service inspection methods, inspection items, inspection basis, selection of safety accessories, inspection of safety accessories and qualification of inspection institutions. Suggestions are made, such as the further improvement of the system of regulations and standards, the supplement and perfection of relevant standards, the enhancement of employees’ safety awareness, the standardization of inspection work behavior, and so on.
Investigation of Relationship Between Microhardness and Charpy Impact Energy for Temper Bead Welding Qualification: Part 2
Authors: Smith Boeing , Ramirez Antonio J. , McCracken Steven L. , Tate Stephen
Published: December 2020

Temper bead (TB) welding is routinely used as an alternative to post weld heat treatment (PWHT) when performing weld repairs on low alloy steels in the nuclear power industry. Historically, TB welding procedures have been qualified by Charpy V-notch (CVN) testing to demonstrate acceptable impact properties in the weld heat affected zone (HAZ).

Part 1 of this work investigated a hardness drop criterion to demonstrate proper HAZ tempering using a vintage heat of SA-508 forged material (see PVP2019-93950). Optimization of hardness test parameters was also a major piece of the Part 1 scope of work. Part 2 of this work adds a more modern heat of SA-508 material and two heats of A-387 F22 material to the study. The overarching goal of this work is to support an alternative hardness test protocol for qualification of temper bead welding (see PVP2015-45663).
INCEFA-PLUS Project: The Impact of Using Fatigue Data Generated From Multiple Specimen Geometries on the Outcome of a Regression Analysis
Authors: Mclennan Alec , Spätig Philippe , Le Roux Jean-Christophe , Waters Joshua , Gill Peter , Beswick Jack , Platts Norman
Published: December 2020

The INCEFA-PLUS project (INcreasing Safety in NPPs by Covering gaps in Environmental Fatigue Assessment) aims to generate and analyse Environmentally-Assisted Fatigue (EAF) experimental data studying parameters such as mean strain, hold times and surface finish. To understand the implications of these parameters for environmental fatigue assessments, these tests were carried out at 300 °C in air and light water reactor primary coolant environments (at 230 °C and 300 °C).

Over the duration of this project around 230 fatigue data points were generated by different organisations using a common testing methodology, but with differing specimen geometries. Of these 230 data points, 23 were obtained from tests done using hollow specimen designs. Recent work comparing the fatigue lives of hollow to those of solid specimens indicates that on average the use of hollow specimens results in reduced fatigue lives. This has been explained in terms of the additional hoop and radial strains applied to the specimen due to the internal pressure of the hollow specimen. Given the examples published in the literature on the topic, the comparison of data generated using hollow and solid specimen geometries within the INCEFA-PLUS database has been a particular concern.

This paper aims to explore the differences between hollow and solid specimen geometries within the INCEFA-PLUS database, highlight the potential risks of including both geometries in a single analysis, and discusses the approach taken by the project to mitigate the identified risks. The work presented in this paper details three approaches for the data obtained from hollow specimens: 1) exclude the data, 2) include the data as is, or 3) include the data with a correction on the strain amplitude. The strain amplitude correction will be based on the theoretical basis presented in Gill et al. [1], and extended to account for the different hollow specimen geometries used across the INCEFA-PLUS programme.

This work demonstrates the robustness of the data analysis performed on the INCEFA-PLUS database to the use of differing specimen geometries. It also develops an explanation for the apparent difference in fatigue life between tests conducted on hollow and solid specimens under test conditions that are nominally the same. Furthermore, this paper builds on the mechanistic understanding presented in Gill et al. [1] and generalises across several Laboratories.
Investigation Into Methods for Determining Moment Ranges at Piping Tees and Branches
Authors: Pellereau Ben , Candler David
Published: December 2020

NB-3600 provides methods for assessing the structural integrity of piping systems. One of the major loading types in piping systems is the moments generated within the pipework to react relative movement of components, thermal expansion and external loads such as gravity or seismic loading.

When assessing a pipe tee or branch, there are three sources of moments that must be considered: from the branch and from the run on both sides of the junction; each of these sets of moments has three components.

The three components of the branch moment can be easily combined using the square root sum of the squares approach to determine a single resultant moment. For the run, the process is more complex as the moments from either side of the junction need to be converted into a single set of component moments before the resultant run moment is obtained. The method for doing this is given in Subparagraph NB-3683.1 of ASME BPVC Section III. Once the three components run moments have been obtained, they are also combined to determine the resultant. The resultant run and branch moments are then multiplied by geometry-dependent stress indices and summed to give a stress range.

For fatigue and shakedown assessments, it is unclear whether the “sign rule” should be applied to the individual load sets before ranging or to the range of each individual component. This potentially results in uncertainty in calculations, leading to unnecessary conservatism and/or repeat calculations.

For this study, 10 randomly generated sets of moments have been applied in a 3D finite element model of a typical pipe tee. The stress intensity ranges obtained from the FE results have been compared with the stress range obtained using the NB-3600 stress indices with the sign rule implemented in three different ways.

The study shows that the sign rule should be applied after ranging the individual moment components; a change to the wording of the code is recommended to confirm this. However, given the levels of conservatism in other parts of the calculation, it is unlikely that any calculations carried out using the sign rule first are non-conservative.
Proposal for a Total Fatigue Life Assessment Methodology That Predicts Fatigue Life From Defect Initiation to Through Wall Leak
Authors: Batten Joseph , Currie Chris , Mann Jonathan , Morley Andrew
Published: December 2020

Even with improvements to remove excessive conservatisms, current fatigue assessment approaches can result in high Cumulative Usage Factors (CUFs) for some analyses. In order to improve plant availability from these assessments and mitigate future changes to design codes, an improvement in understanding in this area is desirable. Hence the proposal for a Life Assessment Methodology (LAM) was created.

The LAM is a concept for an approach based on modelling each stage of fatigue life to predict total fatigue life, as a means of minimising conservatism in an assessment, where necessary. It should also be capable of incorporating statistical methods to assign reliability figures to calculated plant lives.

This paper describes the proposed definition of the LAM and how a proof of concept version of the LAM was developed to assess the Bettis Bechtel Stepped Pipe (BBSP) test. The results were presented with two seeded cases (fixed inputs) and a range of lives corresponding to associated Target Reliabilities (TRs). The Best Estimate (BE) and TR associated lives produced were based on using the latest methods available for calculating Fatigue Initiation (FI) and Fatigue Crack Growth (FCG), whereas the seeded Effective Strain Range (ESR) comparison case used current deterministic assessment methods.

The results for the case study concluded that there is a benefit to pursuing the development of the LAM when compared to traditional assessment methods. It highlighted and quantified the conservatism present in traditional assessment methods for these cases as well as the need to understand the required TR for a specific component as this can have a large effect on the predicted life.

With further refinements to the method, a more realistic and robust output of the total fatigue life distribution (for specific cases) would be obtained, which in turn would allow us to better quantify the conservatism associated with a TR.
Tempering Efficiency Evaluation for Dissimilar Weld Overlays
Authors: Jang Eun , Stewart Jeffrey , Luo Yuxiang , Qu Shijie , Alexandrov Boian , McCracken Steven L. , Tatman Jonathan , Barborak Darren , Penso Jorge A.
Published: December 2020

The objective of this work was to develop a procedure for evaluation and quantification of the tempering efficiency of corrosion resistant weld overlays used in the power generation and oil and gas industries. Three two-layer weld overlays of Alloy 625 on Grade 22 steel plates were produced using GTAW cold wire procedures. Typical welding parameters corresponding to low, medium, and high heat input were utilized. The overlays consisted of nine beads on the first layer and five to seven beads on the second layer. The weld thermal histories experienced in the coarse-grained heat affected zone (CGHAZ) were measured with Type K thermocouples and recorded with a 55 Hz sampling rate. Two rows of seven thermocouples were used in each overlay: one row located in a mid-bead position beneath the center bead of the overlay and the other row located in the nearest bead overlap position. Additionally, one Type C thermocouple was plunged into the weld pool of a second layer weld bead.

The acquired thermal histories and the CGHAZ hardness at the thermocouple locations were evaluated to quantify the tempering efficiency in each welding procedure. The weld thermal histories with peak temperatures between 500°C, assumed as the minimum tempering temperature, and the base metal AC1 temperature were considered as tempering thermal cycles. The number of tempering thermal cycles and the sum of tempering cycle’s peak temperatures in each thermocouple location, as well as the corresponding hardness were used to quantify the tempering response efficiency for each of the three welding procedures. The results of this study will be used for validation of a computational model-based approach for prediction of tempering response and optimization of temper bead welding procedures.
Co(OH)2 powder characterized by x-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS)
Authors: Cole Kevin M. , Kirk Donald W. , Thorpe Steven J.
Published: December 2020

X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS) were performed on as-received analytical grade Co(OH)2 powder. The presence of Co(OH)2 within renewable energy applications is important for enhancing activity. This report provides a detailed photoelectron spectroscopy investigation such that Co(OH)2 can be properly identified in a nondestructive manner. In addition to the survey scan, detailed charge corrected scans for Co 2s, Co 2p, Co 3s, Co 3p, O 1s, O2s, and C 1s surface photoelectron signals are reported. The valence states were analyzed using UPS.
Comprehensive multi-variable analysis of signal-to-noise ratio in dining and social spaces
Authors: Stewart Noral D. , Bridger Joseph F.
Published: December 2020

Difficult communication in dining and social areas is a common problem and the most common acoustical complaint in senior living and healthcare facilities. The signal to noise ratio is the major factor in this and is influenced strongly by architectural design. Prior simplified signal-to-noise-ratio analyses with few variables indicate impracticably high amounts of sound absorption required for acceptable results. This analysis adds the benefit of table-top reflections and the effects of the reverberant part of the signal (partially allotted to noise using known methods) and the direct part of the noise (using a closed-form approximation). It shows that the signal to noise ratio is strongly improved by table-top reflections and improved by (1) increased floor area per person (allowing more absorption and space between tables), (2) rooms with fewer people, (3) smaller table dimensions putting listeners closer to signal talkers, and (4) optimized discussion group size where possible to reduce the number of simultaneous talkers. Increased reverberation time due to higher ceilings is slightly detrimental. While a highly absorptive space is required, consideration of these other factors significantly reduces the required absorption to a more practical level.
A time-aligned plane wave compounding method for high frame rate shear wave elastography
Authors: Capriotti Margherita , Greenleaf James , Urban Matthew W.
Published: December 2020

Shear wave elastography (SWE) is an established ultrasonic imaging technique, that provides quantitative measurements of tissue mechanical properties. This technique relies on the combination of acoustic radiation force push beams to generate propagating shear waves and ultrafast imaging, which allows high two-dimensional imaging frame rates to capture the induced motion. Utilizing coherent plane wave compounding (PWC) can improve signal-to-noise ratio (SNR) of acquired data. While the image quality improves, the pulse repetition frequency (PRF) is reduced, reaching limiting bandwidths to perform SWE. To address these challenges, a method for making SWE measurements with high PRF and SNR is presented. The idea follows the Time Aligned Sequential Tracking method, proposed to allow SWE with enhanced SNR in conventional clinical ultrasound scanners. The time alignment process is applied here to the full field-of-view, acquired by using plane waves transmitted at different angles. In this way, the full PRF and SNR gains are obtained. Results are shown from experiments in tissue-mimicking phantoms, where motion and extracted shear wave velocity are compared for the traditional and proposed data processing schemes. Preliminary results on arterial phantoms are also discussed, to emphasize the beneficial effects of the method in dispersive geometries.
Geometrical modeling and analysis of low frequency acoustical scattering from cylindrically formed schools of swim bladder fish
Authors: Donoso Luis , Feuillade Christopher
Published: December 2020

In previous work [J. Acoust. Soc. Am. 145, 1654 (2019)], a dynamic computer model showed that, depending on interactions between individual fish, fish school behavior typically evolves into discoid, swarming, parallelized, or toroidal geometric forms. At low frequencies, the computed scattering behavior of these schools may be compared using a system of coupled differential equations, and also an “effective medium” method [J. Acoust. Soc. Am. 139, 163–175 (2016)]. The latter technique treats a school as a single scattering object, where the internal medium has a complex propagation wavenumber dependent on the individual fish scattering properties. In the work here, the two-model comparison approach is extended to schools of cylindrical form, modeling them using a superspheroidal paradigm. A “T” matrix method is used to determine the scattering variations for the effective medium computations. The results show that, over much of the applicable frequency range, the scattering variations, as a function of frequency and angle, depend strongly on the specific geometrical shape and dimensions of the school, as well as the scattering properties of the fish constituting the school. This geometrical effect is particularly marked at very low frequencies, where the two models show close agreement. [Work supported by ONRG.]
An analysis of the relationship between linguistic performance and general cognitive abilities in bilingual speakers
Authors: Muscalu Laura M. , Spinu Laura
Published: December 2020

A major issue in bilingualism research is how the bilingual mind processes and reconciles two languages without apparent difficulty when trying to use only one. Research has revealed that when bilinguals produce speech, cross-linguistic competition induced by simultaneous activation of both languages is circumvented by inhibitory and selection mechanisms that allow for phonological articulation of the desired language. Such language-specificprocesses are presumed to derive from domain-general mechanisms that monitor and regulate behavior, to ensure high levels of cognitive performance. To examine the connection between language-specific and domain-general processes, performance on linguistic and nonlinguistic tasks are compared. In our study, Spanish-English participants perform linguistic tasks that induce competition, inhibition, and selection (e.g., production of translation equivalents that are phonologically similar in the two languages) as well as non-linguistic tasks that induce similar challenges (e.g., alternating between visual or auditory stimuli depending on the task requirements). A fine-grained acoustic analysis of timing and accuracy in verbal production (i.e., VOT, vowel formants, frication spectral peak) will be performed. Positive correlations between performances on the two task categories would support the theoretical view that efficient mental manipulation of two languages relies on control mechanisms that are generally involved in higher-order cognitive behavior.
The impact of child age and sentence-type on the acoustics of infant-directed speech
Authors: Geffen Susan , Wang Tianlin
Published: December 2020

Research has demonstrated differences in the characteristics of infant-directed speech (IDS) based on age (Stern et al., 1983) and sentence-type (Geffen and Mintz, 2017) but has not examined the two factors together. The current study evaluates whether the acoustics of IDS differ as a function of child's age and sentence-type. The study combines two corpora of native-English adult speakers. Both Corpus1(9mo) (described in Geffen and Mintz, 2017), from the Brent corpus of the CHILDES database (Brent and Siskind, 2001) and Corpus2 (12mo) (described in Thompson, 2019), from naturalistic home-recordings, included statements, yes/no and wh-questions, and were acoustically coded in Praat. Three 2-way mixed ANOVAs with Age (9 and 12 months; between-subjects factor) and Sentence-Type (S, WH, YN; within-subjects factor) on OverallF0range, FinalVowelDuration, and FinalVowelF0range found main effects of Age, and Age X Sentence-Type interaction for OverallF0range. There was also a significant effect of Age on FinalVowelDuration. Results demonstrated a developmental shift in acoustic characteristics of IDS, with more exaggerated prosody to younger infants, supporting Stern et al. (1983) and suggests that IDS to older children no longer privileges prosody as strongly. Future studies should investigate whether similar developmental adjustments in IDS occur in languages other than English.
Development of formant frequency distributions in American English-speaking elementary school-aged children: A longitudinal study
Authors: Lulich Steven M. , Charles Sherman D.
Published: December 2020

Speech development enters a critical phase in the early elementary years, when learned patterns of phonology and motor control become increasingly entrenched, and developmental speech-language disorders become more difficult to treat. Much attention has been given to early speech development in the preschool years, and a few studies have examined the acoustics of speech development cross-sectionally from Kindergarten to adulthood (see Kent and Vorperian, J Commun Disorders 74, 74–97 (2018)]. To the best of our knowledge, there are no longitudinal acoustic studies of the speech of typically developing children between 5 years and puberty. Although cross-sectional studies provide a general picture of growth, they cannot reveal specific patterns of development and variability. We present acoustic data from an annual, longitudinal study of 8 children between 6 and 10 years of age. All participants are native speakers of Midwest American English. Stimuli included words and sentences from the Goldman-Fristoe Test of Articulation 3rd Edition, as well as a spontaneous speech sample and nonce syllables embedded in a carrier phrase. Frequencies for the first four formants were obtained across the entire stimulus set with Praat, and used to generate formant frequency distributions for each child, in each year.
Contributions of acoustic and lexical cue weighting to individual differences in speech perception
Authors: Giovannone Nikole , Theodore Rachel M.
Published: December 2020

Past research suggests that individuals with weaker receptive language show increased reliance on lexical information for speech perception relative to individuals with stronger receptive language, which may reflect a difference in how acoustic and lexical cues are weighted during online speech processing. Here we investigated whether this relationship is the consequence of removing natural correlations between acoustic and lexical cues in speech input, as in the specific stimulus distributions used in previous research. Two groups of adult participants completed measures of receptive and expressive language ability in addition to a measure of lexical recruitment (i.e., a phonetic identification task to measure the Ganong effect). In the high conflict group, the stimulus input distributions put acoustic and lexical cues in high competition; in the low conflict group, this competition was reduced. The results showed that (1) the Ganong effect was larger in the low compared to the high conflict condition, (2) the Ganong effect was larger for those with weaker compared to stronger receptive language, and (3) the relationship between the Ganong effect and receptive language was not mediated by conflict. These results demonstrate increased reliance on lexical information among those with weaker receptive language, suggesting that listeners with weaker language abilities down-weight acoustic cues and rely more heavily on lexical knowledge even when natural acoustic and lexical cue correlations are maintained in the input.
Wait, was that bruise or brews? Utilizing acoustic cues in word recognition of morphologically simple and complex homophones
Authors: Kim Yun J.
Published: December 2020

This study investigates listeners' sensitivity to acoustic cues in recognizing morphologically simple (e.g., bruise, freeze) and complex (e.g., brews, frees) homophones. Previous studies demonstrated that native speakers of English use distinct acoustic cues in producing morphologically simple versus complex forms (e.g., Walsh and Parker, 1983; Plag et al., 2014; Seyfarthet al., 2018). For example, Seyfarth et al. (2018) reported that both the stem (e.g., brew, free) and the segment “si” are longer in duration in morphologically complex words compared to those in monomorphemic counterparts. It still remains in question whether listeners utilize this information in recognizing morphologically simple versus complex homophones. To answer this question, a listening comprehension study is conducted: 20 participants are asked to select the word that they thought they heard. The stimuli have three conditions: (1) both the s and stem length are longer in complex words than simple words, (2) only the s is longer, and (3) only the stem is longer. The influence of each durational cue on the listeners' responses and their response time is analyzed. The results will show whether the distinct acoustic cues available in the input are meaningfully coded and used in speech perception.
Perceptual analysis on modality change: Is this “Banana” a statement or a yes-no question?
Authors: Câmara Beatriz O.
Published: December 2020

This paper attempts to observe what change in the F0 contour is crucial to make Brazilian speakers change their perception of a recording of the word “banana” from a neutral statement to a neutral yes-no question. The Praat software was used to create a close copy stylization ('t Hart 1991) of the word banana,“, recorded in the two modalities mentioned before; and, to gradually modify the melodic contour of the statement ”banana" until it finally had the same characteristics of the yes-no question contour that was used as a basis. To see which stimuli would change listeners' interpretation of the statment banana to a yes/no question banana, a perception test was made with twenty Brazilian Portuguese native speakers (11 female and 9 male) around the ages of 20 to 60-years-old. The autossegmental-metrical theory by Pierrehumbert (1980) was used to describe Brazilian's intonational patterns for neutral statement and yes-no question.
Does vowel recognition relate to pitch?
Authors: Maurer Dieter , d'Heureuse Christian , Leemann Heidy
Published: December 2020

It was shown that, for vowel sounds, the spectrum relates to fundamental frequency (fo) and the spectral envelope is ambiguous, often representing two or three different vowel qualities if fo is varied substantially. Thus, from a speech perception perspective, vowel quality is indicated to relate to the pitch of a vowel sound. In this contribution, a concept is outlined addressing the experimental question of the relationship of vowel recognition and pitch. According to this concept, two or three harmonics are extracted near the spectral peaks of a natural vowel sound, representing assumed F1–F2 or F1–F2–F3, and the lowest harmonic(s) below the first spectral peak are added. Based on a single extracted harmonics pattern, a series of sounds are synthesised stepwise attenuating the levels of the lowest harmonics with the aim to effect a low-to-high transition of the highest common harmonics factor and pitch. Pitch level and vowel recognition of the sounds is then investigated by means of listening tests. Results of a first pilot study based on sounds of mid-closed vowels /e, ø, o/ confirmed the vowel–pitch relation hypothesis and also revealed cases of sounds with double-pitch and double-vowel recognition.
Effects of phonetic and indexical variability on talker normalization
Authors: Drown Lee , Theodore Rachel M.
Published: December 2020

Our current work builds on past research demonstrating that listeners experience a processing cost when hearing speech from multiple talkers compared to a single talker. This processing cost is thought to reflect a normalization process during which listeners adjust the mapping to speech sounds to accommodate talker differences in speech production. In the current studies, we use a speeded word identification paradigm to measure processing time for word recognition in single- vs. mixed-talker blocks, and manipulate within-talker and between-talker variability along both phonetic (e.g., vowel formants) and indexical (e.g., fundamental frequency) dimensions. The results to date suggest that listeners incur processing costs given variability in either dimension, even in single-talker blocks, which raises critical methodological considerations for examining talker normalization in addition to informing theories of talker normalization.
Using ultrasound imaging to investigate top-down prediction effect on speech motor planning
Authors: Ning Li-Hsin
Published: December 2020

This study investigated whether the activation of speech motor system could be highly influenced by top-down prediction in picture naming when we are listening to prior context. A the picture norming task was administered to 30 native Mandarin speakers (NMSs) to ensure there was an agreement upon the concept names. The pictures (21 out of 31) where the naming accuracy was higher than 0.85 were selected. We then created two stem sentences for each picture/word, one matching the word, and the other one mismatching the word. The 42 tokens (21 words × 2 stems) were given to another group of 30 NMSs to rate the acceptability. Finally, 12 pairs out of the 21 pairs were selected for ultrasound recording. In the ultrasound recording, the audio signals of stem sentences were played followed by the target pictures displayed on the computer screen. The other group of 30 NMSs had to name the pictures as soon as possible. The results show that articulatory adjustments (lowering the tongue tip) were made at the vowel onset when there was a mismatch between predicted words and to-be-said words. It seems that we react to unexpected words at the early time course of speech motor activation.
Neural pitch tracking of nonnative lexical tones in 7 and 11-month-old infants
Authors: Zhao Tian , Llanos Fernando , Kuhl Patricia K. , Chandrasekaran Bharath
Published: December 2020

Infants' sensitivity to nonnative speech contrasts decline between 6 and 12 months, a period that is considered a ‘sensitivity period' for phonetic learning. However, it is yet unknown whether earlier sensory encoding of nonnative speech is also affected by during this key period of transition. To address this question, we recorded frequency-following responses (FFRs) from monolingual English-learning infants at 7 and 11 months of age while they listened to a high-front vowel with a nonnative low-dipping Mandarin lexical tone. The FFR is a scalp-recorded potential that reflects phase-locking activities from cortical and subcortical ensembles in the auditory system. Sixteen infants had at least 1500 clean trials at both ages after data processing. For each age, we assessed the sensory encoding of the nonnative tone by bootstrapping the group-level FFR. We resampled with replacement one thousand16-subject groups. In each iteration, we randomly selected and averaged across 1500 trials of FFR from each subject. The fundamental frequency (f0) of each group-averaged FFR was then used to correlate with the f0 of the stimulus. The results show that the FFR-stim correlation was significantly lower (i.e., worse sensory encoding) at 11 months than at 7 months, suggesting an early sensory marker that may reflect ‘perceptual narrowing'.
Late positive response indexes neural sensitivity to emotional prosody differences in spoken words
Authors: Kao Chieh , Zhang Yang
Published: December 2020

Emotional prosody is an important social cue that conveys the speaker's intention. Proper recognition of emotional prosody facilitates the interpretation of spoken language. Previous event-related potential (ERP) studies successfully documented an early negative (mismatch negativity, MMN) and a later positive (P3a) involuntary neural responses to detecting a change in emotional speech prosody (Schirmer et al., 2005; Zora et al., 2019). Nonetheless, these ERP components were elicited by controlling the linguistic content of the speech stimuli. It remains unclear whether natural affective prosody across varying linguistic carriers would elicit similar activation patterns. The current study adopted the multi-feature oddball paradigm to investigate the ERP responses to three basic emotional prosodiesâ€”happy, angry, and sadâ€”embedded in varying monosyllabic English words. Thirty-three adult listeners (female = 23) completed the experiment. Unlike the previous reports, there was not a clear MMN response to the detection of emotional prosody patterns in the stimuli. But a late positive response (LPR) component was observed frontal-centrally in response to changes in affective prosody. Linear mixed-effect models further confirmed the presence of significantly larger LPRs to happy prosody than angry or sad prosody, suggesting that the LPR is a more reliable neural marker for emotional prosody recognition.
Implementing the open master hearing aid on a system-on-chip field programmable gate array
Authors: Snider Ross , Blunt Matthew , Vannoy Trevor , Sobrero Dustin , Wickham Dylan , Davis Tyler
Published: December 2020

System-on-Chip (SoC) Field Programmable Gate Arrays (FPGAs) are ideal for embedded real-time signal processing because of their high performance and low latency. Here we describe the process of implementing the Open Master Hearing Aid [1] on an SoC FPGA. We started by creating a FFT based Simulink model to implement hardware friendly frequency-domain processing. This model implements Short-Time Fourier Transform processing in an overlap-and-add architecture. This was followed by porting additional openMHA processing blocks, such as dynamic range compression, to Simulink. Once the hearing aid Simulink model was finished, Mathwork's HDL Coder was used to create VHDL. To create an interactive system, we used Audio Logic's code generation tools to generate the infrastructure needed to communicate with the hearing aid processor in real-time; this includes generating device drivers that allow Linux to communicate with the hearing aid processor, as well as a custom web application with an autogenerated GUI. This example provides an open reference design for those who may be interested in low latency FPGA based data flow architectures. 1. www.openmha.org
Dynamic range compression of sound mixtures
Authors: Corey Ryan M. , Singer Andrew C.
Published: December 2020

Nearly all advanced hearing aids use dynamic range compression (DRC) to make quiet sounds louder and loud sounds quieter. A form of nonlinear gain control, DRC can help to improve listening comfort, but it can also introduce distortion in the presence of multiple competing sounds. The gain applied to all sounds in a mixture is determined by the level of the loudest sound; the signals therefore modulate each other. It has been widely observed that DRC performs poorly in noisy environments, but there has been little mathematical analysis of the interaction between compression and noise. In this work, we use an idealized model, equating the envelope of a signal with its statistical variance, to analyze the effects of DRC on mixtures of uncorrelated signals. We show that when DRC is applied to a mixture, the effective compression applied to each sound is weaker than it would have been in isolation. Similarly, we analyze how DRC algorithms alter the long-term signal-to-noise ratio of a sound mixture. This analysis can help us to develop DRC algorithms that are more robust to noise and improve the performance of hearing aids in the complex environments where they are needed most.
Modifying the Welch method to estimate power spectral percentiles
Authors: Schwock Felix , Abadi Shima
Published: December 2020

Welch overlap segment averaging method is a popular approach for estimating power spectra of stochastic signals due to its computational efficiency, its ability to scale estimation variance, and its potential to reduce spectral leakage. However, in its original form, the Welch method is prone to spectral outliers caused by transient signals. A computationally efficient solution is to replace the common mean averaging for each frequency bin by a percentile estimation, which has proven to be a robust alternative to the original method. The statistical properties of this approach, such as estimation variance and limiting distribution, have not yet been analyzed in greater detail. In this talk, we present respective expressions for the Welch percentile estimator by using concepts from order statistics and spectral estimation theory. The Welch percentile estimator is applied to the ocean ambient noise data which are compromised by transient signals from an Acoustic Doppler Current Profiler (ADCP) co-located with the hydrophone. Based on the statistical properties of the percentile estimation, confidence intervals for the ocean noise levels have been computed to provide a measure for the estimation quality.
CDMA-based multi-domain communications network for marine robots
Authors: Patel Jay , Seto Mae
Published: December 2020

A cross-domain communications network for above and below water marine robots, based on code-division multiple access (CDMA), is reported. CDMA is a promising physical layer and multiple access technique for underwater acoustic sensor networks as it: (i) is robust to frequency selective fading, (ii) compensates for multi-path effects at the receiver, and (iii) allows receivers to distinguish amongst signals simultaneously transmitted by multiple devices. Consequently, CDMA increases channel re-use and reduces packet retransmissions, which results in decreased energy consumption and increased network throughput. The proposed CDMA network for autonomous co-ordination and networking is applied to marine robots separated by extended ranges to transmit images/information from underwater to above-water. The work involves a complete communications protocol stack from the physical to the application layer. Simulations of the proposed network were performed with Network Simulator-3 (NS-3). The proposed protocol leverages CDMA properties to achieve multiple access to the scarce underwater bandwidth while previous reported work with underwater channels only consider CDMA for the physical layer encoding. Simulations shows the proposed underwater acoustic network protocol outperforms other existing ones. The next step is preliminary testing in-water.