Noise Test Research Articles

Blast Exposure Associations With Hearing Loss and Self-Reported Hearing Difficulty.

Examine associations between military blast exposures on hearing loss and self-reported hearing difficulties among Active-Duty Service Members (ADSM) and Veterans from the Noise Outcomes in Servicemembers Epidemiology (NOISE) study. Cross-sectional. Multi-institutional tertiary referral centers. Blast exposure was assessed with a comprehensive blast questionnaire. Outcome measures included pure-tone hearing thresholds; Speech Recognition in Noise Test; Hearing Handicap Inventory for Adults (HHIA); and Speech, Spatial and Qualities of Hearing Scale (SSQ)-12. Twenty-one percent (102/494) of ADSM and 36.8% (196/533) of Veterans self-reported blast exposure. Compared to ADSM without blast exposure, blast-exposed ADSM had increased odds of high frequency (3-8 kHz) and extended-high frequency (9-16 kHz) hearing loss (odds ratio [OR] = 2.5, CI: 1.3, 4.7; OR = 3.7, CI: 1.9, 7.0, respectively). ADSM and Veterans with blast exposure were more likely than their nonblast exposed counterparts to report hearing difficulty on the HHIA (OR = 1.9, CI: 1.1, 3.3; OR = 2.1, CI: 1.4, 3.2, respectively). Those with self-reported blast exposure also had lower SSQ-12 scores (ADSM mean difference = -0.6, CI: -1.0, -0.1; Veteran mean difference: -0.9, CI: -1.3, -0.5). Results suggest that blast exposure is a prevalent source of hearing injury in the military. We found that among ADSM, blast exposure was associated with hearing loss, predominately in the higher frequencies. Blast exposure was associated with poorer self-perceived hearing ability in ADSM and Veterans. IRB: #FWH20180143H Joint Base San Antonio (JBSA) Military Healthcare System; #3159/9495 Joint VA Portland Health Care System (VAPORHCS) Oregon Health and Science University (OHSU).

A Scoping Review and Meta-Analysis of the Relations Between Cognition and Cochlear Implant Outcomes and the Effect of Quiet Versus Noise Testing Conditions.

Evidence continues to emerge of associations between cochlear implant (CI) outcomes and cognitive functions in postlingually deafened adults. While there are multiple factors that appear to affect these associations, the impact of speech recognition background testing conditions (i.e., in quiet versus noise) has not been systematically explored. The two aims of this study were to (1) identify associations between speech recognition following cochlear implantation and performance on cognitive tasks, and to (2) investigate the impact of speech testing in quiet versus noise on these associations. Ultimately, we want to understand the conditions that impact this complex relationship between CI outcomes and cognition. A scoping review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed on published literature evaluating the relation between outcomes of cochlear implantation and cognition. The current review evaluates 39 papers that reported associations between over 30 cognitive assessments and speech recognition tests in adult patients with CIs. Six cognitive domains were evaluated: Global Cognition, Inhibition-Concentration, Memory and Learning, Controlled Fluency, Verbal Fluency, and Visuospatial Organization. Meta-analysis was conducted on three cognitive assessments among 12 studies to evaluate relations with speech recognition outcomes. Subgroup analyses were performed to identify whether speech recognition testing in quiet versus in background noise impacted its association with cognitive performance. Significant associations between cognition and speech recognition in a background of quiet or noise were found in 69% of studies. Tests of Global Cognition and Inhibition-Concentration skills resulted in the highest overall frequency of significant associations with speech recognition (45% and 57%, respectively). Despite the modest proportion of significant associations reported, pooling effect sizes across samples through meta-analysis revealed a moderate positive correlation between tests of Global Cognition ( r = +0.37, p < 0.01) as well as Verbal Fluency ( r = +0.44, p < 0.01) and postoperative speech recognition skills. Tests of Memory and Learning are most frequently utilized in the setting of CI (in 26 of 39 included studies), yet meta-analysis revealed nonsignificant associations with speech recognition performance in a background of quiet ( r = +0.30, p = 0.18), and noise ( r = -0.06, p = 0.78). Background conditions of speech recognition testing may influence the relation between speech recognition outcomes and cognition. The magnitude of this effect of testing conditions on this relationship appears to vary depending on the cognitive construct being assessed. Overall, Global Cognition and Inhibition-Concentration skills are potentially useful in explaining speech recognition skills following cochlear implantation. Future work should continue to evaluate these relations to appropriately unify cognitive testing opportunities in the setting of cochlear implantation.

Cost-Effective Data Acquisition Systems for Advanced Structural Health Monitoring.

With the growing demand for infrastructure and transportation facilities, the need for advanced structural health monitoring (SHM) systems is critical. This study introduces two innovative, cost-effective, standalone, and open-source data acquisition devices designed to enhance SHM through the latest sensing technologies. The first device, termed CEDAS_acc, integrates the ADXL355 MEMS accelerometer with a RaspberryPi mini-computer, ideal for measuring strong ground motions and assessing structural modal properties during forced vibration tests and structural monitoring of mid-rise buildings. The second device, CEDAS_geo, incorporates the SM24 geophone sensor with a Raspberry Pi, designed for weak ground motion measurements, making it suitable for seismograph networks, seismological research, and early warning systems. Both devices function as acceleration/velocity Data Acquisition Systems (DAS) and standalone data loggers, featuring hardware components such as a single-board mini-computer, sensors, Analog-to-Digital Converters (ADCs), and micro-SD cards housed in protective casings. The CEDAS_acc includes a triaxial MEMS accelerometer with three ADCs, while the CEDAS_geo uses horizontal and vertical geophone elements with an ADC board. To validate these devices, rigorous tests were conducted. Offset Test, conducted by placing the sensor on a leveled flat surface in six orientations, demonstrating the accelerometer's ability to provide accurate measurements using gravity as a reference; Frequency Response Test, performed at the Gebze Technical University Earthquake and Structure Laboratory (GTU-ESL), comparing the devices' responses to the GURALP-5TDE reference sensor, with CEDAS_acc evaluated on a shaking table and CEDAS_geo's performance assessed using ambient vibration records; and Noise Test, executed in a low-noise rural area to determine the intrinsic noise of CEDAS_geo, showing its capability to capture vibrations lower than ambient noise levels. Further field tests were conducted on a 10-story reinforced concrete building in Gaziantep, Turkey, instrumented with 8 CEDAS_acc and 1 CEDAS_geo devices. The building's response to a magnitude 3.2 earthquake and ambient vibrations was analyzed, comparing results to the GURALP-5TDE reference sensors and demonstrating the devices' accuracy in capturing peak accelerations and modal frequencies with minimal deviations. The study also introduced the Record Analyzer (RECANA) web application for managing data analysis on CEDAS devices, supporting various data formats, and providing tools for filtering, calibrating, and exporting data. This comprehensive study presents valuable, practical solutions for SHM, enhancing accessibility, reliability, and efficiency in structural and seismic monitoring applications and offering robust alternatives to traditional, costlier systems.

Analytical model of magnetic Barkhausen noise testing on surface-modified ferromagnetic plates with stress distributions

Surface treatment is a critical technology in engineering that enhances the mechanical properties of materials, in which the stress state within the material and the thickness of the surface modification layer are essential for optimizing performance. Magnetic Barkhausen Noise (MBN) serves as an effective nondestructive evaluation technique for ferromagnetic structures. In this work, we develop an analytical model that incorporates the attenuation mechanism of the MBN signal strength, and the strength of the stress-induced magnetic Barkhausen excitation (MBE) as determined by the magneto-mechanical constitutive law of the material. The proposed theoretical model can accurately characterize the MBN signal influenced by internal stresses and surface modification layers, as confirmed by comparison with existing experimental results. The theoretical analysis shows the influence of internal stress fields, layer dimensions, and electromagnetic properties on the MBN signal, revealing a positive relationship between signal intensity and the thickness of surface modification layer and the magnitude of internal stresses. This research provides a valuable reference for interpreting MBN signals and evaluating internal stress distributions for surface-modified ferromagnetic plates.

Helium screw compressor for 5tpd large-scale hydrogen liquefier

Liquid hydrogen has promising applications in various industries. As an important heart role, compressors are essential for efficient hydrogen liquefaction. This study introduced a novel profile screw compressor employed in large-scale hydrogen liquefaction processes. The development addressed the challenges associated with large-scale rotors, high pressure differences, and demanding capacity or torque requirements. By utilizing a 5/7-lobe combination of male to female rotors, this technology effectively tackled issues related to rotor dynamics, such as heavy-load rotor stiffness and dynamic balance. The profile design followed hydrodynamics principles, reducing viscosity loss and oil–gas flow loss at high speeds, large flow rates, and significant pressure differences. The profile curve’s curvature and geometric configuration were tailored to the specific pressure state during compression. In high-pressure areas, the profile remained relatively flat to maintain machining accuracy. While in low-pressure areas, the curvature was increased, and the meshing clearance was reduced to minimize helium leakage. Experimental tests conducted under conditions similar to actual hydrogen liquefaction processes have successfully validated the theoretical profile design and the newly developed multi-point oil injection cooling technologies. These advancements have led to an impressive isothermal efficiency of 58.1 % for the entire screw set. Furthermore, the stability and reliability of the compressor were verified through noise and vibration signal testing. The results demonstrated that the compressor operated with noise levels below 96 dB (A) and vibration levels below 7 mm/s, further ensured its suitability for large-scale cryogenic applications. These compressors have successfully run stably on the 5.17 tpd (ton per day) hydrogen liquefier. Overall, this research would significantly contribute to the advancement of screw compressors and large-scale cryogenic technology.

Spatial-sign-based high-dimensional white noises test

In this study, we explore the problem of hypothesis testing for white noise in high-dimensional settings, where the dimension of the random vector may exceed the sample sizes. We introduce a test procedure based on spatial-sign for high-dimensional white noise testing. This new spatial-sign-based test statistic is designed to emulate the test statistic proposed by Paindaveine and Verdebout [(2016). On high-dimensional sign tests. Bernoulli, 22(3), 1745–1769.], but under a more generalized scatter matrix assumption. We establish the asymptotic null distribution and provide the asymptotic relative efficiency of our test in comparison with the test proposed by Feng et al. [(2022). Testing for high-dimensional white noise. arXiv:2211.02964.] under certain specific alternative hypotheses. Simulation studies further validate the efficiency and robustness of our test, particularly for heavy-tailed distributions.

Evaluation of the wear mechanism of ferromagnetic materials based on magnetic barkhausen noise

ABSTRACT As a typical form of damage, wear greatly affects the service properties of products, and non-destructive evaluation of the degree of wear is urgently needed. In this paper, the wear degree of AISI 1045 steel was evaluated by magnetic Barkhausen noise (MBN) testing. The root mean square (RMS) and full width at half maximum (FWHM) of MBN were extracted to establish the quantitative relationships between the tribological indicators and the stress state. The results indicate that the RMS decreases linearly and the FWHM increases quadratically with increasing tribological indicators, which can distinguish among different wear stages, including abrasive, adhesive and fatigue wear. However, the RMS shows a complicated nonlinear relation with the residual stress during the wear process. In addition, the MBN energy parameter is also calculated to reveal the features of the hysteresis loop at the wear scar. Both the coercivity H c and the maximum magnetic permeability μ max are linearly related to the tribological indicators and quadratically related to the stress, which reflects the effect of tribo-magnetisation on the MBN signals. The variation mechanism of MBN under different wear stages is attributed to the combined effect of plastic deformation and the stress state by microstructure observations.

Accurate determination of impact ionization coefficient ratio and temperature dependence of InGaAs/InP avalanche photodiodes

We propose a broadband noise test method (10 Hz–1 MHz) using a direct power method to measure the excess noise of InGaAs/InP avalanche photodiodes (APDs) with a separate absorption, grading, charge, and multiplication structure. By this means, the impact ionization coefficient ratio (the k value) can be accurately determined. Compared with previous studies, this method can distinguish between low-frequency noise and excess noise, so for an appropriate high frequency spectral range, the excess noise can be analyzed without mixing in other noise information. Three different APDs fabricated in-house with different diameters (12, 25, and 60 µm) were investigated using the above-mentioned method under temperatures varying from −10 to −40 °C. Our findings showed that the k value of the APDs decreased as the temperature decreased. When the temperature decreased to −40 °C, the k value of the 12, 25, and 60 µm diameter diodes was as low as 0.1, 0.3, and 0.2, respectively. The measurement results are consistent with our device design and not only provide useful information for the future selection of device materials and structures but also demonstrate the feasibility of the broadband noise measurement method in the accurate determination of the k value. It indicates that low excess noise can be achieved by utilizing the temperature dependence of k.

The role of hidden hearing loss in tinnitus: Insights from early markers of peripheral hearing damage

Since the presence of tinnitus is not always associated with audiometric hearing loss, it has been hypothesized that hidden hearing loss may act as a potential trigger for increased central gain along the neural pathway leading to tinnitus perception. In recent years, the study of hidden hearing loss has improved with the discovery of cochlear synaptopathy and several objective diagnostic markers. This study investigated three potential markers of peripheral hidden hearing loss in subjects with tinnitus: extended high-frequency audiometric thresholds, the auditory brainstem response, and the envelope following response. In addition, speech intelligibility was measured as a functional outcome measurement of hidden hearing loss. To account for age-related hidden hearing loss, participants were grouped according to age, presence of tinnitus, and audiometric thresholds. Group comparisons were conducted to differentiate between age- and tinnitus-related effects of hidden hearing loss. All three markers revealed age-related differences, whereas no differences were observed between the tinnitus and non-tinnitus groups. However, the older tinnitus group showed improved performance on low-pass filtered speech in noise tests compared to the older non-tinnitus group. These low-pass speech in noise scores were significantly correlated with tinnitus distress, as indicated using questionnaires, and could be related to the presence of hyperacusis. Based on our observations, cochlear synaptopathy does not appear to be the underlying cause of tinnitus. The improvement in low-pass speech-in-noise could be explained by enhanced temporal fine structure encoding or hyperacusis. Therefore, we recommend that future tinnitus research takes into account age-related factors, explores low-frequency encoding, and thoroughly assesses hyperacusis.

Reverse design and additive manufacturing of furniture protective foot covers

Reverse design and additive manufacturing technologies are fast ways to develop customised products. In this study, furniture protective foot covers were taken as the design object. Using flexible filaments of polylactic acid (PLA) and the development process of reverse design to additive manufacturing, the protective foot covers were designed and manufactured to fit the shape of the chair feet. Furniture protective foot covers have high practical value. They have a certain buffering effect, avoiding the damage caused by the collision of furniture feet with the ground when moving furniture; secondly, they reduce the noise generated by the collision of furniture feet with the ground, creating a quiet and comfortable home environment. According to the finite element simulation results, the maximum stress value of the European-style chair installed with protective foot covers was decreased by 90.8% in the case of vertical fall, which verifies that the protective foot covers have an obvious buffering effect. Noise test results show that the noise of the European-style chair installed with protective foot covers was decreased by 51.0%, which verifies that the protective foot covers have an obvious quieting effect.

Experimental research on dynamic responses and hydrodynamic pressures of deep-water bridge piers under seismic and wave actions

Earthquakes and extreme waves pose significant threats to the safety of offshore bridges, particularly in deep-water environments. The temporal sequence of earthquakes and waves and the specific type of earthquake are critical factors that contribute to the potential risks involved. This study aimed to fill a key knowledge gap by conducting a comprehensive series of physical tests on a deep-water bridge pier at a scale factor of 1:30. White noise tests, shaking table tests, wavemaker tests, and combined shaking table and wavemaker tests were carried out. Near-field pulsed earthquakes, far-field long-period earthquakes and earthquake-wave phase differences were examined in the tests. The test results indicate that the presence of water has a noticeable impact on the natural frequency, particularly the 2nd-order frequency, of bridge piers, which may significantly influence the dynamic responses of high bridge piers. The effects of water–pier interactions are further intensified by seismic actions such as the pulsed Loma Prieta and long-period Chi-Chi earthquakes. Moreover, the earthquake-induced hydrodynamic pressures on the upstream and downstream faces of the pier are nearly identical, whereas there is a notable difference when the pressures are caused by incident waves. The magnitude of the combined earthquake and wave responses in relation to the individual responses is influenced by the earthquake–wave phase differences, and the combined responses are less than the sum of the individual responses.

Hebrew Digits in Noise (DIN) Test in Cochlear Implant Users and Normal Hearing Listeners.

This study aimed to compare the Hebrew version of the digits-in-noise (DIN) thresholds among cochlear implant (CI) users and their normal-hearing (NH) counterparts, explore the influence of age on these thresholds, examine the effects of early auditory exposure versus its absence on DIN threshold, and assess the correlation between DIN thresholds and other speech perception tests. A total of 13 children with CI (aged 5.5-11 years), 15 pre-lingual CI users (aged 14-30 years), and 15 post-lingual CI users (aged 22-77 years), and their age-matched NH controls (n = 45) participated in the study. Speech perception tasks, including the DIN test, one-syllable word test, and sentence identification tasks in various auditory conditions, served as the main outcome measures. The results indicated that CI users exhibited higher speech reception thresholds in noise across all age groups compared to NH peers, with no significant difference between pre-lingual and post-lingual CI users. Significant differences were also observed in monosyllabic word and sentence accuracy in both quiet and noise conditions between CI and NH groups. Furthermore, correlations were observed between the DIN and other speech perception tests. The study concludes that CI users require a notably higher signal-to-noise ratio to discern digits in noise, underscoring the DIN test's utility in assessing speech recognition capabilities in CI users while emphasizing the need for a comprehensive test battery to fully gauge their speech perception abilities.

The acoustic-vibration characteristics of cylindrical roller bearings with raceway failures: Simulation and experiment

This paper presents a mathematical model for cylindrical roller bearings, the precision noise test and simulation investigation are employed, the discussion focuses on the systematic investigation of the vibration characteristics, noise properties, and noise transmission attributes of defective bearings. The findings indicate that severe displacement oscillations of rollers and oil film oscillations can be observed due to the raceway fault, the average slip rate of rollers is seriously affected, resulting in a reduction in the operational stability of the cage. The noise shock is also introduced, which is primarily reflected in the mid-frequency range (670–8000 Hz) of the spectrum, leading to a deviation from the normal distribution of noise data points. This characteristic makes it challenging to detect noticeable shock signals when testing bearing noise at a distance. This research holds the promise of deepening comprehension of faulty bearing dynamics, thereby furnishing richer means for precise fault diagnosis.

Phase Noise Analysis Performance Improvement, Testing and Stabilization of Microwave Frequency Source

Phase Noise Analysis Performance Improvement, Testing and Stabilization of Microwave Frequency Source

Experimental study on the characteristics of R1150/R600 mixed refrigerant Joule-Thomson low-temperature freezer

In this paper, a low-temperature freezer based on Joule-Thomson system with a variable frequency fan was developed by using the natural binary mixture of R1150/R600. The experiment results demonstrated the feasibility of using this mixture to obtain the low freezing temperature below −70 °C. It could be found that when the concentration of R1150 was 27.5 %, it had the lowest daily energy consumption of 5.94 kWh/24 h. Furthermore, the influences of different fan speeds and active fan speed control on the cool-down characteristics of the system were also studied. The results indicated that lower fan speed in the early stage could effectively improve the cool-down performance. It was 51 min faster than that of the fixed operating fan speed under the optimal fan speed control at the target freezing temperature. Finally, the noise test of the freezer was carried out, and the influences of on–off temperature and fan speed on the system noise were also analyzed. The noise level of the system is between 46.71 dB and 51.62 dB, which is acceptable for the users. Moreover, the influence of fan speed on system noise was greater than that of different on–off temperatures. Therefore, improving the heat exchange efficiency of the condenser to reduce the fan speed is the possible direction of noise reduction for low-temperature freezers in the future.

Integrated bimodal fitting and binaural streaming technology outcomes for unilateral cochlear implant users

Objective Adults typically receive only one cochlear implant (CI) due to cost constraints, with a contralateral hearing aid recommended when there is aidable hearing. Standard hearing aids differ from a CI in terms of processing strategy and function as a separate entity, requiring the user to integrate the disparate signals. Integrated bimodal technology has recently been introduced to address this challenge. The aim of the study was to investigate the performance of unilateral CI users with and without an integrated bimodal fitting and determine whether binaural streaming technology offers additional benefit. Study sample Twenty-six CI users using integrated bimodal technology. Design Repeated measures where outcomes and user experience were assessed using a functional test battery more representative of real life listening (speech perception in noise tests, localisation test, tracking test) and the speech, spatial and qualities-of-hearing scale (SSQ). Results Bimodal outcomes were significantly better than for CI alone. Speech perception in noise improvements ranged from 1.4 dB to 3.5 dB depending on the location of speech and noise. The localisation and tracking tests, and the SSQ also showed significant improvements. Binaural streaming offered additional improvement (1.2 dB to 6.1 dB on the different speech tests). Conclusions Integrated bimodal and binaural streaming technology improved the performance of unilateral CI users.

Adverse Effects of Extended high frequency Hearing Impairment on Digit in Noise Perception

Purpose: The present study aims at comparing the adverse effects of EHF hearing loss with Digit In Noise perception, between two age groups-Young adults and Early adulthood.Methods: A total of 30 participants aged between 18 to 25 years as Young adults group and 26 to 35 years as early adulthood group were included in the study. All the participants were having EHF hearing loss with normal conventional audiogram. Digit in Noise test was carried out for these subjects. Digit in Noise recognition threshold was considered here.Results: When compared to young adults group, the early adulthood population exhibited poorer thresholds at EHFs as well as 95% of the participants in this group showed poor scores in DIN test. Among the young adults group, 46.6% showed poor DIN scores.Conclusions: Poor DIN recognition thresholds along with EHF loss despite normal conventional audiogram results necessitate the inclusion of EHF audiometry and Speech in noise test as part of the routine audiological evaluations. This helps in early detection, monitoring and prevention of hearing loss even during the third decade of human life.

Central auditory functions in post-COVID-19 adults; a case control study

BackgroundThis study aimed to evaluate the central auditory abilities in post-coronavirus disease 2019 (COVID-19) adults by using Central Auditory Tests (CATs). This study included a complaining group (GI), a non-complaining group (GII), and a control healthy group (GIII). All subjects were evaluated using CATsResultsResults demonstrated statistically significant differences across groups as regards Speech Perception in Noise Test (SPIN), Duration Pattern Sequence Test (DPT), Gap in Noise Test (GIN), and Memory Test (ANOVA, p-value ≤ 0.05). The post-hoc test revealed that, except for recognition memory, both study groups showed statistically significant differences from the control group. Also, significant differences were detected between both GI and GII groups regarding SPIN−10 signal-to-noise ratio (S/N), DPT, GIN threshold, memory for content, and memory for sequenceConclusionsCOVID-19 led to central auditory processing disorders (c)APD.

ANALYSIS OF A NEW TYPE OF ELECTRIC POWER STEERINGGEAR WITH TWO PINIONS ENGAGED ON THE SAME SETOF TEETH ON THE RACK

Electric power steering is the most commonly used solution in passenger cars. It is a more economical andreliable solution than the hydraulic equivalent. Its main parts are usually the rack, pinion, and worm wheel,which are subject to wear during driving. A steering gear that works incorrectly poses a direct threat to thesafety of the driver and other road users. The paper presents various types of electric power steering gears,with a particular emphasis on the problems that arise during the design of the pinion and rack. In this paper,a new electric power steering system consisting of a steering gear with two pinions working on a commontoothing of the rack (TPEPS) is proposed. The benefits of placing two pinions on one tooth set of a steeringrack are described, which eliminates many problems during production, and thus allows the reduction inproduction costs. As part of the analysis, design challenges for a new type of transmission are presented,taking into account key customer requirements, with a particular emphasis on durability and ensuring thedesired noise level, which is important due to the replacement of cars with an internal combustion drive withan electric drive. This paper presents selected friction and noise test results for a new power steering system.A comparison is made with a system that has two pinions and different teeth on the rack (DPEPS). The resultsindicate that the new system could become an alternative solution due to its lower friction value and lowernoise.

Quantum analogues of white noise delta functions

In this paper, we construct a quantum analogue of a white noise delta function. For our main purpose, we first discuss several white noise delta functions, specially, an infinite-dimensional analogue of Donsker’s delta function. Then as a general setting, we construct white noise delta functions on white noise test functionals and we derive a Cauchy problem whose solution is given by the white noise delta function. Also, we prove that the white noise delta function is an eigenvector of the exotic Laplacian. By applying the canonical topological isomorphisms between the spaces of white noise operators and the spaces of white noise functionals, we formulate a quantum analogue of the white noise delta function which satisfies a quantum white noise differential equation associated with the quantum Volterra Laplacian. Finally, we prove that quantum analogue of the white noise delta function is an eigenoperator of the quantum exotic Laplacian.