Breaking Conditions Research Articles

Influence of Phonatory Break Duration and Pause Time on Auditory-Perceptual Ratings of Speech Acceptability and Listener Comfort in Adductor-Type Laryngeal Dystonia

IntroductionThis study empirically evaluated the influence of phonatory break duration and pause time on auditory-perceptual measures of speech produced by 26 adult speakers diagnosed with adductor-type laryngeal dystonia (AdLD). Type of StudyExperimental. MethodsFifteen inexperienced, young adult normal-hearing listeners provided ratings of speech acceptability and listener comfort for samples of running speech. Four phonatory break and pause time conditions were assessed using visual analog scaling methods. All stimuli were randomized for presentation and listeners were presented with experimental stimuli in a counterbalanced manner. ResultsResults indicate that the duration of phonatory breaks directly influenced listener ratings of speech acceptability (P < 0.001) and listener comfort (P < 0.001), with significant differences between original and modified recordings for both. Speech acceptability and listener comfort ratings were strongly correlated across all timing conditions (r = 0.85–0.97). ConclusionsThe duration of phonatory breaks and pauses have significantly influence judgments of speech acceptability and listener comfort for AdLD. This suggests that temporal factors such as phonatory break duration and pause time in AdLD may carry substantial negative impact on listeners’ perception relative to other auditory-perceptual features that co-exist in the signal.

Affective and cognitive restoration: comparing the restorative role of indoor plants and guided meditation

This study investigated whether indoor plants were as effective as a guided meditation for enabling psychological recovery after fatigue induced by the abbreviated vigilance task. Sixty students were randomly assigned to an indoor plant, guided meditation, or control rest-break condition. The psychological processes most in need of recovery were identified as cognitive and affective restoration. Measures of affect, stress, and working memory were taken before and after the vigilance task, and again after a rest intervention. The vigilance task-induced fatigue as shown by a significant vigilance decrement and also significantly lowered positive affect and cognitive engagement, and significantly increased distress across all three conditions. After exposure to the break interventions, distress significantly decreased for participants in the indoor plant break condition while distress significantly decreased and engagement significantly increased in the guided meditation break condition. Indoor plants and guided meditation had a small, but significant positive impact on affective restoration and no significant impact on cognitive restoration. Practitioner summary: Indoor plants are a cost-effective green ergonomics intervention in offices. This study found that a rest break with indoor plants was as effective as a rest break with guided meditation for affective restoration after fatigue from a vigilance task. Abbreviations ART attention restoration theory LCD liquid crystal display PANAS positive and negative affect schedule DSSQ S: dundee stress state questionnaire - short version BDS backward digit span ANOVA analysis of variance CI confidence interval M mean

Sensitivity of a one-line longshore shoreline change model to the mean wave direction

The sensitivity of a one-line longshore shoreline change model to the incident wave direction is evaluated at Narrabeen Beach (Australia). As previously observed, the application of the one-line model using wave conditions generated along the 10-m depth contour produces a long-term reorientation of the coastline, with an initial transition period and then a new stable equilibrium during the 10-year period from 2005 to 2015. However, this coastline change in shoreline planform shape is not observed in the shoreline position measurements. The source of this error is investigated by assuming that it is caused by biases in the incident wave direction and by using a Monte Carlo approach to search for the optimal set of wave angle bias corrections to apply at each cross-shore transect. The obtained optimal values enable the one-line model to reproduce accurately the shoreline planform, and they are coherent with estimates of the wave breaking angle obtained independently using a nearshore wave propagation model. Then, using the corrected wave angle time series as a reference, a second Monte Carlo analysis is completed to investigate the sensitivity of the model to errors in the mean wave direction drawn from Gaussian distributions with varying standard deviations. The analysis shows the range of expected errors in shoreline position for an estimated range of errors in the mean wave direction at Narrabeen beach. This work highlights the importance of considering the sensitivity of one-line longshore model simulations to errors in the incident wave angle, which can be relatively large given the uncertainties in spectral wave model estimates of wave direction, in wave buoy observations, and in wave propagation methods or input bathymetry used to estimate wave breaking conditions.

Multimode -symmetry thresholds and third-order exceptional points in coupled dielectric waveguides with loss and gain

A pair of coupled dielectric waveguides with balanced loss and gain is the basic system for observing the phenomena of parity-time () symmetry and exceptional points (EPs). We use the multimode analytical approach to study the peculiarities of interaction between the modes excited in such an archetypal structure. With this approach, the conditions for symmetry breaking are obtained in the special case of the hybrid HE and EH modes resulting in the ordinary second-order EPs (or -symmetry thresholds). The coupling of modes with the different azimuthal indices (the TM01 and HE21 modes in our study) generates the uncommon types of EPs. First, there are the so-called multimode -symmetry thresholds due to interaction of hybrid and transverse modes. Second, the third-order EPs appear as a result of three-modes degeneracy of real eigenvalues. It is noteworthy that an increase in the EPs order is achieved without both breaking the symmetry and introducing additional elements into the waveguide structure. The results obtained with the multimode analytical approach are in perfect agreement with the independent full-wave simulations.

An experimental study on the motion of solid spheres under solitary wave attack

In the present study, the motion of a single and the motion and collision of two spheres on a horizontal area under solitary wave attack are investigated, constituting a unique and integrated dataset. Sixteen experimental cases are considered on four experimental configurations changing the number of spheres, the porosity of the bottom, water levels, and the breaking condition of the solitary waves (non-breaking or breaking). The motion of the spheres is tracked using a color-detection-based image-processing algorithm. The experiments reveal four significant results: (i) The rate of damping on the porous bottom is 1.65 times of impermeable bottom on average. (ii) The water level changes the characteristics of the motion of the spheres significantly due to the friction forces and vortex structures created by the interaction of waves with moving spheres. (iii) The dimensionless terminal velocities of the spheres in the non-breaking cases are 1.38 times of breaking solitary wave cases on average. (iv) The type of solitary wave and the water level significantly affect the collision behavior; however, the bottom condition does not have an apparent contribution to the collision behavior.

Histogram as features for fault detection of multi point cutting tool – A data driven approach

In the milling process, the condition of the tool is the important factor that determines the quality of the machined product. Hence, monitoring the condition of the tool becomes essential. There should be a mechanism to find out whether the tool is in good condition or affected by some faults. If so, the fault in the tool should be known to the user in order to prevent unnecessary breakdown. Face milling tool condition monitoring is taken up for the study. Tools with various conditions were considered viz., Tool in good condition, tool in broken condition, tool with the flaking condition, and tool with flank wear. The machining parameters were varied with three different values such as spindle speed (250 rpm, 300 rpm, and 350 rpm), feed rate (14 mm/min 20 mm/min and 28 mm/min), and depth of cut (0.5 mm, 0.75 mm, and 1 mm) and the percentage variation of the considered machining parameters with the average is found as 17% for spindle speed, 33% and 38% for feed rate, and 33% for depth of cut. Vibration signals have been acquired with the help of an accelerometer for various conditions of the tool under varying machining parameters. The raw signals were then processed and were extracted thirty-five histogram features. From the pool of features, only the useful features were selected by the decision tree algorithm. A set of rules have been generated from the useful features and fed as an input to the fuzzy classifier. The same set of features was used to classify the faults with the Artificial Neural Network (ANN) algorithm and their fault classification capacities were analyzed. The results show that both the algorithms exhibit promising results and ensure the robustness of the signals. Also, the best classifier is proposed for the fault classification of the milling tool.

Experimental and Numerical Study on the Wave, Surge, and Structure Interactions on a Coastal Residential Building

Lee, D.; Park, H.; Shin, S., and Cox, D.T., 2021. Experimental and numerical study on the wave, surge, and structure interactions on a coastal residential building. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 156–160. Coconut Creek (Florida), ISSN 0749-0208. Residential structures in the low-lying coastal region are often suffered from devastate coastal disasters, like storms and tsunamis. To minimize the loss and improve the resilience of a coastal community, it is crucial to understand structural damage and failure mechanism under extreme from extreme coastal events. Large-scale laboratory experiments of wood-framed residential houses were conducted to investigate the wave and surge effect on the structure and the structural failure mechanism. The tests were conducted by changing a surge level, wave period, and wave height condition, and measure hydro-kinematics and structural damage process. LIDAR scanning was conducted to collect the data of damage proportion on the structure during series of wave and surge conditions. A three-dimensional RANS model, olaFlow, was used to verify our numerical model, and applied to understand hydrodynamics near the structure. Three different wave breaking conditions, including non-breaking, breaking, and broken wave are tested and consequent wave induced forces on structure are compared for both undamaged structure and damaged structure conditions. The numerical model results showed a good agreement with the experimental results in water surface and velocity. The numerical results of wave induced force in damaged conditions showed 28∼43% smaller than those in undamaged conditions. This finding highlight that the damage level of a structure could affect predicting wave load on the structure.

Experimental study of erosion by waves on the lakeshore of lateritic soils

Many countries use hydropower as their main source of power generation. One of the factors responsible for erosion in hydroelectric reservoir margins is the action of wind-induced waves, which increases sedimentation and reduces their storage capacity. Despite potential economic and environmental damages, research into wave erosion processes on reservoir margins are found mainly in cohesive soils from cold regions. Research on erosion by waves of cohesive soils from savannah regions, which are commonly found in tropical reservoirs, is incipient; studies evaluating breaking and non-breaking wave conditions on this type of erosion are especially important. This work presents the results from 18 water wave channel experiments which were conducted to investigate the erosional processes by waves on lateritic soils, under breaking wave and non-breaking wave conditions, as well as determining the spatial distribution of the resulting sediments. Lateritic soil samples were placed on the wave channel and different conditions were tested. Wave frequencies varied from 0.272 to 0.999 Hz on four different beach slope angles of 22.50, 30.00, 45.00, and 60.00 degrees. In 80% of the tests, the erosion rate varied positively in a nonlinear form with the increase of the accumulated wave power. However, when the waves broke, erosion rate sometimes varied negatively and the sediment production tended to be reduced. High precision 3D surveys showed a good agreement between the maximum depth of the eroded surfaces and the power increase of the waves. The average roughness of the samples increased in 90% of the tests. The spatial distribution of sediments and their grain size distributions were also investigated. The waves’ driving forces were incapable of transporting the sediments away from their source of origin and, therefore, were not able to change the natural distributions of the grains with the simulated conditions.

Failure analysis of aircraft main landing gear cylinder support

The main concern in aircraft structures is flight safety. One of the constraints to consider when designing safe aircraft parts is weight. The design of the landing gear structures is difficult because it must ensure flight safety without adding excessive weight.During takeoff, the main landing gear of a cargo plane did not retract. The landing procedure went off without a hitch. The maintenance crew disassembled and inspected the main landing gear to determine the source of the problem. The main landing gear cylinder support was discovered to be in broken condition. The part was broken at the 90-degree corner region. The location of the fracture is subjected to high stresses in service conditions especially during braking with a heavily loaded aircraft.Detailed destructive and, non-destructive evaluation procedures were applied to reveal the root cause or causes of the failure. The determination of the root cause is crucial to prevent a similar failure in the future.Visual inspection, electrical conductivity test, fractography, microstructural evaluation, chemical analysis, hardness test were applied to the part. After examination, it was determined that the support had failed due to fatigue. The conditions of use, low radius geometry in the crack origin, rough machined surface, and pitting corrosion all played a role in the failure.

Breaking Wave Hazard Estimation Model for the U.S. Atlantic Coast

Abstract As offshore wind development is in its infancy along the U.S. Atlantic Coast challenges arise due to the effects of strong storms such as hurricanes. Breaking waves on offshore structures induced by hurricanes are of particular concern to offshore structures due to high magnitude impulse loads caused by wave slamming. Prediction of breaking wave hazards is important in offshore design for load cases using long mean return periods of environmental conditions. A breaking wave hazard estimation model (BWHEM) is introduced that provides a means for assessing breaking hazard at long mean return periods over a large domain along the U.S. Atlantic Coast. The BWHEM combines commonly used breaking criteria with the Inverse First Order Method of producing environmental contours and is applied in a numerical study using a catalog of stochastic hurricanes. The result of the study shows that breaking wave hazard estimation is highly sensitive to the breaking criteria chosen. Criteria including wave steepness and seafloor slope were found to predict breaking conditions at shorter return periods than criteria with only wave height and water depth taken into consideration. Breaking hazard was found to be most important for locations closer to the coast, where breaking was predicted to occur at lower mean return periods than locations further offshore.

Experimental study of bound triad interactions across a dissipative surf zone under different wave breaking conditions

This study experimentally investigates the development and decay of bound energy fractions due to positive and negative interactions (b2p and b2n, respectively) applying bispectral analysis. It was revealed that the Ursell number is the most successful parameter to estimate the variation patterns of b2p and b2n. The experimental waves included 27 waves with three offshore wave heights, three periods, and three offshore water depths propagating over a mild slope of 1:30. A wide variety of wave nonlinearity and bound coupling intensities were observed across the experimental dissipative surf zone. For a wave propagating toward the shore, the corresponding Ursell numbers for the relative maximum values of b2p and b2n are 0.27 and 0.22, respectively. The ratio of significant wave height to water depth corresponding to these extreme values for positive and negative triads are ~0.4 and ~0.32, respectively. The highest values of b2p and b2n for a progressive wave can be predicted as a function of the Ursell number using two new proposed experimental formulations. The sub-harmonics are more persistent during wave-breaking conditions than super-harmonics due to lower wave steepness. The biphase values of self-coupling of the spectral peak are attained negative for waves with Ursell numbers greater than 0.35.

An exploratory study comparing three work-rest schedules during simulated repetitive precision work

The pattern of work and rest can influence both physical fatigue and task performance in manual operations. However, there is relatively limited evidence regarding the influences of specific work/rest schedules in tasks requiring high repetitiveness and precision demands, along with relatively low exertion levels. Eighteen participants completed an exploratory study that simulated such tasks, to compare the effects of three distinct work/rest schedules (i.e., short frequent [short] and long infrequent breaks [long], and a self-selected schedule) on muscle fatigue, task performance (in terms of accuracy and speed), and preference. Schedules with long or self-selected breaks generally induced less muscle fatigue, compared with the short break condition. Participants preferred the self-selected condition the most and the long-break condition the least. The different schedules tested did not influence task performance. A self-selected schedule may be beneficial for repetitive precision task, to achieve a balance across muscle fatigue, task performance, and individual preference. Practitioner Summary: Influences of three work/rest schedules (i.e., short and long breaks, and a self-selected schedule) on fatigue, performance, and preference were explored during repetitive precision tasks. Schedules with long or self-selected breaks induced less muscle fatigue and none of the three schedules influenced performance. A self-selected schedule was the most preferred.

Effect of Ergodic and Non-Ergodic Fluctuations on a Charge Diffusing in a Stochastic Magnetic Field.

In this paper, we study the basic problem of a charged particle in a stochastic magnetic field. We consider dichotomous fluctuations of the magnetic field where the sojourn time in one of the two states are distributed according to a given waiting-time distribution either with Poisson or non-Poisson statistics, including as well the case of distributions with diverging mean time between changes of the field, corresponding to an ergodicity breaking condition. We provide analytical and numerical results for all cases evaluating the average and the second moment of the position and velocity of the particle. We show that the field fluctuations induce diffusion of the charge with either normal or anomalous properties, depending on the statistics of the fluctuations, with distinct regimes from those observed, e.g., in standard Continuous-Time Random Walk models.

Sliding-wave acceleration of ions in high-density gas jet targets.

A hybrid mechanism of ion acceleration is investigated which demonstrates the higher spectral density of protons at high energies. The interaction of few-cycle terrawatt laser pulses with near-critical density gas target is studied with the help of two-dimensional particle-in-cell simulation. The generation of few MeV protons with high spectral concentration near cutoff is attributed to the propagation of solitary waves in the decaying density profile of the gas jet. Plasma dynamics at longer time scale is explained by semianalytical modeling and conditions for solitary wave breaking are presented.

Comments on the symmetry breaking condition in MacDowell–Mansouri action

In this work, we study the symmetry breaking conditions, given by a (anti)de Sitter-valued vector field, of a full (anti)de Sitter-invariant MacDowell–Mansouri inspired action. We show that under these conditions, the action breaks down to General Relativity with a cosmological constant, the four-dimensional topological invariants, as well as the Holst term. We obtain the equations of motion of this action, and analyze the symmetry breaking conditions.

Ka-Band Radar Cross-Section of Breaking Wind Waves

The effective normalized radar cross section (NRCS) of breaking waves, σwb, is empirically derived based on joint synchronized Ka-band radar and video records of the sea surface from a research tower. The σwb is a key parameter that, along with the breaker footprint fraction, Q, defines the contribution of non-polarized backscattering, NP =σwbQ, to the total sea surface NRCS. Combined with the right representation of the regular Bragg and specular backscattering components, the NP component is fundamental to model and interpret sea surface radar measurements. As the first step, the difference between NRCS values for breaking and non-breaking conditions is scaled with the optically-observed Q and compared with the geometric optics model of breaker backscattering. Optically-derived Q might not be optimal to represent the effect of breaking waves on the radar measurements. Alternatively, we rely on the breaking crest length that is firmly detected by the video technique and the empirically estimated breaker decay (inverse wavelength) scale in the direction of breaking wave propagation. A simplified model of breaker NRCS is then proposed using the geometric optics approach. This semi-analytical model parameterizes the along-wave breaker decay from reported breaker roughness spectra, obtained in laboratory experiments with mechanically-generated breakers. These proposed empirical breaker NRCS estimates agree satisfactorily with observations.

Оценка эффективности применения электронных инициирующих устройств «ИСКРА-Т» по условиям дробления и сейсмического действия торцевых взрывов

The paper justifies the optimal delay time in non-synchronous fan blasting with the most optimal delay time between the holes being 15 ms. Experiments were conducted to assess the breaking conditions and seismic effects of face blasts in the underground conditions of the Rasvumchorrsky mine using the Iskra-T electronic initiating systems with delay times of 10, 15 and 20 ms. With the delay times of 10 and 15 ms there is no clear segregation of the blast stages and interference of compression waves, created by consecutively blasted charges, takes place, while their joint interaction leads to insignificant increase of the seismic effects on the mine workings. According to the results of ore drawing monitoring, the number of boulders with the above delay times did not exceed 10 pieces for the whole blasted volume for each round. With the delay time of 20 ms a clear segregation of the blast stages was obtained with the minimum number of 7 boulders per blast. In order to ensure acceptable rock mass fragmentation quality and reduce the seismic effect of blasting on the mine workings, as well as to preserve the pilot holes drilled, it is advisable to use reverse initiation with non-synchronized fan blasting with the delay time of 20 ms between the holes.

Synoptic-scale precursors of landslides in the western Himalaya and Karakoram

In the Upper Indus Basin (UIB), precipitation associated with synoptic-scale circulations impinges on the complex and steep orography of the western Himalaya and Karakoram. Heavy rainfall often falls over the foothills, frequently triggering landslides there. This study explores the role of these synoptic-scale circulations – extratropical western disturbances (WDs) and tropical depressions (TDs) – in producing the conducive conditions necessary to trigger landslides, using data from the NASA Global Landslide Catalog and WD and TD track databases.During the winter (October to April), UIB landslides peak in February and occur at a rate of 0.05 day−1, 61% of which are associated with the passage of a WD. They are most common when a WD is located within a few hundred kilometres of 30°N, and significantly rarer if the WD is north of 40°N. WDs provide moist southwesterly flow from the Arabian Sea and Mediterranean Sea to the UIB, resulting in large-scale precipitation, but landslide probability is not related to WD intensity. Non-WD winter landslides are associated with small-scale orographic precipitation that we hypothesise is due to cloudbursts.During the summer (May to September), UIB landslides peak in August and occur at a rate of 0.11 day−1, 60% of which are associated with TD activity. Many of these TDs are found over central India, slightly south of the climatological monsoon trough, where they provide strong monsoonal southeasterlies to the UIB flowing along the Himalayas. Increased landslide frequency is also associated with TD activity over the southern Bay of Bengal (BoB), and it is hypothesised that this is related to monsoon break conditions. Landslide frequency is significantly correlated with TD intensity. Non-TD landslides are associated with a northwestward extension of the monsoon trough, providing southeasterly barrier flow to the UIB.Implications for forecasting and climate change are discussed.

Experimental study for characteristics of slamming loads on bow of a ship-type FPSO under breaking and irregular wave conditions

An experimental investigation of the characteristics of the slamming impact loads on the bow of a ship-type Floating Production Storage and Offloading (FPSO) under breaking and irregular wave conditions was conducted. The breaking waves were generated by the focusing wave method and three different heading angles were applied. To examine the repeatability of the slamming loads, the model experiments were repeated 20 times for each heading condition. The slamming impact loads were measured using 15 force sensors attached to the bow of the FPSO unit model, while force panels were used to measure the local impact loads. The locations of the largest slamming impact loads were observed to vary with the heading angle. Two types of slamming impact loads were identified and damping was also observed in the slamming impact load with two peaks. Irregular wave tests conducted under oblique wave conditions were further used to investigate the characteristics of the slamming impact loads, and the velocities of the directional sway and roll motions were found to be significant determinants of the slamming impact load.

Mathematical modelling of thermal stresses within the borehole walls in terms of plasma action

Purpose is the development of a mathematical model to study and describe thermal processes within the borehole wall in terms of plasma-based rock breaking. Methods. The following has been applied: theoretical analysis in the framework of a theory of brittle thermoelasticity breaking, methods of mathematical modeling, and computational experiment. Findings. Brief information on the results of the development of advanced plasma-based technology for borehole reaming for hard mineral mining has been represented. The results of industrial tests of plasma plant of 150-200 kW·s power with plasma-generating gas in the air for hard rock breaking have been represented. The plant and plasma-based technology of borehole reaming were tested in underground conditions of Kryvbas mines while reaming a perimeter hole to drive a ventilation rise in silicate-magnetite quartzites. A mathematical model has been proposed to analyze heat and mechanical fields in the rock during the plasma-based action on the borehole walls. Numerical studies of the temperature dynamics and thermal stresses within the borehole-surrounding rock layer have been carried out. It has been demonstrated that if low-temperature plasma is used (Т = 3500-4000°С), thermal compressing stresses are induced within the thin rock layer; the stresses may exceed the boundary admissible ones. It has been identified that plasma-based effect on the borehole wall makes it possible to create the conditions for intense rock fracturing and breaking. Originality. Solution of a new problem of thermoelastic state of a borehole wall in terms of plasma action has been obtained. The proposed mathematical model has been formulated in a cylindrical coordinate system and considers convective and radiation heat exchange between a plasma jet and a borehole wall. Practical implications. The obtained results make it possible to assess the rock state depending on the plasma jet parameters. The proposed methods of calculations will help carry out research to evaluate breaking parameters (the required heating time, thickness of the heated layer, and approximate spall dimensions) and develop different methods for the breaking process control.