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The increase in industrial activities has raised concerns regarding air quality in urban areas within Malawi. To assess the source apportionment of air quality parameters (AQPs) and noise levels, concentrations of AQPs (CO, TSP, PM 2.5, PM10) and noise levels were monitored at 15 sites in Makata, Limbe, Maselema, Chirimba, and Maone during dry and wet seasons, respectively. Active mobile multi-gas monitors and a Dylos DC1100 PRO Laser Particle Counter (2018 model) were used to monitor AQPs, while Integrated Sound Level Meters were used to measure noise levels. Monitoring and analysis were guided by the World Health Organization (WHO) and Malawi Standards (MS). A Positive Matrix Factorization (PMF) model was used to determine source apportionment of AQPs, and matrix trajectories analysed air mass movement. In the wet season, the average concentration values of CO, TSP, PM10, and PM2.5 were 0.49 ± 0.65 mg/m3, 85.03 ± 62.18 µg/m3, 14.65 ± 8.13 µg/m3, and 11.52 ± 7.19 µg/m3, respectively. Dry season average concentration values increased to 1.31 ± 0.81 mg/m3, 99.86± 30.06 µg/m3, 24.35 ± 9.53 µg/m3, and 18.28 ± 7.14 µg/m3. Noise levels remained below public MS and WHO standards (85 dB). Positive correlations between AQPs and noise levels were observed, strengthening from weak in the dry season to moderately strong in the wet season. PMF analysis identified key factors influencing AQPs accumulation, emphasizing the need for periodic sampling to monitor seasonal pollution trends, considering potential impacts on public health and environmental sustainability. Further studies should look at factors affecting the dynamics of PMF in Blantyre City. [ABSTRACT FROM AUTHOR]

Having one's life threatened by a disease like ovarian cancer is the single most crucial thing in the whole world. It is difficult to achieve high performance without sacrificing computational efficiency; the results of the denoising process are not as good as they could be; the proposed models are nonconvex and involve several manually chosen parameters, which provides some leeway to boost denoising performance; the methods generally involve a complex optimisation problem in the testing stage; Here at DnCNN, we've developed our own version of the deep ii learning model, a discriminative learning technique. The goal was to eliminate the need for the iterative optimisation technique at the time it was being evaluated. The goal was to avoid having to go through testing altogether, thus this was done. It is highly advised to use a Deep CNN model, the efficacy of which can be evaluated by comparing it to that of more traditional filters and pre-trained DnCNN. The Deep CNN strategy has been shown to be the best solution to minimise noise when an image is destroyed by Gaussian or speckle noise with known or unknown noise levels. This is because Deep CNN uses convolutional neural networks, which are trained using data. This is because convolutional neural networks, which are the foundation of Deep CNN, are designed to learn from data and then use that learning to make predictions. Deep CNN achieves a 98.45% accuracy rate during testing, with an error rate of just 0.002%. [ABSTRACT FROM AUTHOR]

This study employs a novel approach of comparing the effects of different types of mobility options on noise levels around arterials with the use of noise-level based passenger car unit (PCU) factors. The study area of this research was Karachi, Pakistan, although the methodology can be applied elsewhere. A regression model was developed for calculating PCUs based on noise level. To ensure maximum spread of data collection and variance in levels of traffic presence, the data was collected from five arterials of Karachi. Traffic volume count included mobility options of motorbikes, cars, pickup, rickshaws, buses, and trucks. It was found that the noise-based PCU factors differ greatly compared to those calculated based on traffic flow. Highest noise based PCU factor was for trucks, used for freight mobility, and lowest one was for rickshaws, a very common shared mobility option for passengers. These equivalency factors can provide a convenient approach for prediction of noise levels, along arterials, for transportation planners at the project development stage. Consequently, they can be utilized for planning and development of sustainable and healthy communities. Their importance is also justified on the basis of recent trend which includes introduction of various shared mobility options in Karachi, such as metro bus, online delivery, and ride-hiring services. [ABSTRACT FROM AUTHOR]

Noise levels in a dental office can be produced by different specialty instruments. Exposure to high levels of noise (unwanted sounds) may cause auditory and non-auditory health problems in dentists. The aim of this study was to (a) measure the noise levels within different clinics and laboratories of the Department of Dentistry, School of Health Sciences of the National and Kapodistrian University of Athens, (b) promote information sharing on this serious health issue among stakeholders, and (c) collect data to organize preventive measures for students and personnel (faculty members, collaborators, administrative, and technical staff). Since the study did not apply to acoustics and acoustic measurements, a digital sound level meter and noise-integrating dosimeters with an analogue electronic transducer were used to collect data from certain postgraduate (PG) and undergraduate (UG) clinics and laboratories (LAB) during peak working periods and with a duration of 1 h per clinic/lab. Both personal (dosimeters) and static (area monitoring) noise exposure assessments were evaluated, resulting in various teaching-related activities in dental clinics. At all locations, the maximum exposure limit value of 87 dB(A) was not exceeded. However, chairside personal measurements during ultrasonic work revealed that the lower exposure action value of 80 dB(A) was exceeded. PG clinics were noisier than UG. LAB training settings, even with the new equipment, were close to the upper exposure limit due to the simultaneous use of airotors. In this context, targeted research and investigations into measures are proposed to safeguard the health and safety of students during their duties at the dental school. [ABSTRACT FROM AUTHOR]

The unknown boundary condition identification problems of the 2-D Laplace equation are considered in this paper. Based on the good characteristics of the B-spline wavelet and Tikhonov regularization method (TRM), a new regularization B-spline wavelet method (RBPWM) is proposed. The novel algorithm could be regarded as one kind of wavelet mesh-free, non-iterative numerical scheme that converts the boundary condition identification problem into a large-scale algebraic equation system that can be solved in a single step. However, the coefficient matrix of the algebraic equation system is ill-conditioned, which will lead to an unstable solution for the case of higher-level noise. The Tikhonov regularization method (TRM) is used to achieve a steady numerical solution to this problem. The current work of this paper has studied four examples with different simulated noise levels for different boundary conditions. The efficiency and accuracy of the presented algorithm are verified with the numerical simulation. [ABSTRACT FROM AUTHOR]

The present study experimentally investigates the aerodynamic noise from the flow around cylinders of square and equilateral triangle cross-sections at different angles of incidence (α). The cylinder models have a side dimension of 10 mm and a span of 300 mm. The free stream velocity (U 0 ) is in the range of 12–36 m/s, and the corresponding Reynolds numbers are 7.8 × 103 to 2.3 × 104, which is in the subcritical flow regime. The characteristic acoustic tones are generated at α = 30° and 45° for square and triangular cylinders. The frequency of acoustic tones linearly increases with the free stream velocity, and the corresponding Strouhal numbers are found to be in the range of 0.13–0.16. Depending on the angle of incidence, the overall sound pressure level is higher than the background noise by 4–24 dB for the square cylinder and 3–15 dB for the triangular cylinder at U 0 = 36 m/s. The highest noise level of the square cylinder is 90 dB at α = 45° and 79 dB at α = 30° for the triangular cylinder. The spectral scaling with the sixth power of the free stream velocity indicates the dipole behaviour of the acoustic tones. The mean and root-mean-square velocity profiles in the wake region characterise the noise emissions at different angles of incidence. The comparative acoustic study of the non-circular cylinders with a circular counterpart showed that the highest noise level is from the square cylinder at α = 45°. The directivity study shows that the noise level of the square cylinder at α = 45° at 90° angular location (θ) is higher by 6.5 dB than that at θ = 30°. [ABSTRACT FROM AUTHOR]

Specific energy (SE) is the energy required to excavate a unit volume of rock. It is a very important variable in the planning and designing of excavation projects, mining, and petroleum industry and depends on rock properties. This investigation reports about the prediction of SE, the effect of properties of rocks on SE, and the effect of operational variables on SE using sound levels created during the drilling process. Initially, SE was determined for all selected rock types and a correlation was developed between SE and physico-mechanical rock properties (PMRP) and operating variables. The developed prediction models were validated using determination coefficients (R2), the t-test, F-test, and performance predictions i.e. values account for (VAF), root mean square error (RMSE) and mean absolute percentage error (MAPE). For SE, the R2 values obtained a range from 75.58% to 78.76%, RMSE values obtained a range from 0.074411 to 0.578601, VAF values obtained a range from 72.826808 to 84.155813 and MAPE values obtained a range from 0.061218 to 2.321007 for selected rock samples and also, t and F values obtained below the tabulated values. Concerning SE's relation to PMRP, it was observed that SE increased with increasing uniaxial compressive strength, Brazilian tensile strength, and dry density and decreased with increasing abrasivity. For PMRP, the R2 values obtained from 92.25%, 90.99%, 47.15%, 93.39%, corresponded to uniaxial compressive strength, Brazilian tensile strength, density, and abrasivity. Similarly, regarding SE's relation with operational variables, it was observed that SE decreased with increasing drill bit diameters, penetration rates, and drill bit speed. The developed models can be served in the exploration and excavation projects for the prediction of specific energy. [ABSTRACT FROM AUTHOR]

In this study, A-weighted noise levels were recorded for the entire day (24 h) at each site along the major urban roads of Kurukshetra city in India. The traffic flow (volume and composition) was also recorded simultaneously. Thereafter, the relevant noise and traffic descriptors were computed to assess the traffic noise pollution. The equivalent 2-hourly traffic noise levels, L e q , 2 h , exhibited a somewhat cyclic pattern having noise crests and troughs over the 24 h in the case of all the four studied urban roads, thus identifying the peak and lean noise hours. The equivalent day time noise levels ( L D ) and night time noise levels ( L N ) were in the range of 68.06 – 80.73 dB(A) and 44.12 – 70.91 dB(A) respectively, exceeding the permissible levels as per Indian standards and WHO guidelines at all sites, except L N at two sites. The day-night average noise levels with 24-h’ base time, L D N , was above WHO limits of 70 dB(A) barring five sites. The proposed relationship between L D N and passenger car unit (PCU) per hour has the potential application in estimating noise levels from traffic flow data with a high coefficient of determination of 0.8774. The noise climate ( N C ) and traffic noise index ( T N I ) varied from 21.62 to 46.01 dB(A) and 116.16 – 187.53 respectively. [ABSTRACT FROM AUTHOR]

Continuous time series data from geomagnetic observatories are increasingly contaminated by anthropogenic noise related to developing socio-economic activities. More and more sophisticated techniques of data processing are used to eliminate this noise; nonetheless, some of it cannot be removed. The main sources of noise in the Hyderabad (HYB) data are vehicular traffic, power lines and a power station, 500 m to 1 km away. During the nationwide COVID-19 pandemic lockdown from 24 March to 17 May 2020, both road and metro rail traffic came to a complete halt. The data from this time interval give us an opportunity to evaluate the effects of the absence of traffic-generated noise sources. We found noticeable differences in the noise levels present in vector and scalar variation data, due to the vehicular noise observed before and during the lockdown periods. Noise spectrum estimates quantify the reduction in the noise levels during this period. We also noticed decreased scatter in absolute values of the H (horizontal), D (declination), Z (vertical) and I (inclination) components of the geomagnetic field during lockdown. The details of increased data quality in the absence of traffic-generated noise sources are discussed. [ABSTRACT FROM AUTHOR]

This study aims to assess noise levels in selected outdoor and indoor microenvironments in a University community in Oman. The perception of noise levels within the Sultan Qaboos University campus was investigated through a survey study. Also, the effect of exposed noise levels on annoyance and sleep disturbance were predicted including their potential risk on cardiovascular health. Among all the measured parameters, it was found that outdoor (41.6%-50%) and indoor (38.5%-46.2%) microenvironments have exceeded the critical levels of 55 dB during morning and afternoon periods. The respondents (698 people) identified traffic and indoor building-related activities as the main sources of noise levels but the majority (44%) of them rated their impact as low. However, more than 30% of the respondents considered traffic as the main contributor to University noise levels. The percentage of highly annoyed persons was predicted to be high in outdoor areas especially in the residential (25%) and near the hospital (13%) areas. However, indoor environments including construction materials and structures labs (14%) showed similar annoyance rates. Also, the percentage of high sleep disturbed persons was found higher in residential areas (7.4%) areas compared to hospital areas (5.3%) locations. The study concluded that there might be an association between the exposed noise levels and the risk of developing cardiovascular diseases. This is the first study that has provided a high spatial variability noise exposure levels across a University environment in Oman, this will contribute to designing future sustainable mitigation strategies to improve the health and well-being of the exposed population. The study has provided a baseline knowledge needed for future epidemiological studies. [ABSTRACT FROM AUTHOR]

Noise pollution has been rising as a critical issue in recent days particularly for the people living in urban areas. This study has been conducted to find out the effects of traffic induced noise on nearby residential building through 3D noise mapping with and without noise Barriers. Monitoring has been carried out at various densely populated preselected locations of Delhi, India. Thereafter, 3D noise mapping has been done using hourly average noise levels for the locations exposed with maximum noise. The developed 3D noise map shows the variation of noise level along X, Y and Z direction for all selected locations before and after installation of noise barriers. Moreover, the result also shows that exact assessment of noise impact is possible through 3D noise mapping, when a multistory building close to the source of noise is taken into consideration. This paper also elaborates the adequate height, distance and NRC value of noise barrier to reduce the effect of road traffic noise on nearby high rise building. Reduction pattern of noise level can easily be visualized and evaluated by using these maps. This type of study could support decision makers during adaptation of suitable remedial measures.

There is adequate evidence from epidemiological studies showing an association between noise exposures and incidence of cardiovascular diseases and cognitive impairment among exposed populations. This study aimed to investigate noise exposure levels in an airport region and their effects on the nearby two neighborhood communities (i.e., Al Seeb and Bawshar). To achieve this, noise levels were measured across 15 different points within the communities for more than 3 weeks at a median distance of 3.5 km from the airport runways using a sound level analyzer. In addition, we conducted an online social survey in a random sampling of a total of 913 residents who were living closer to the airport. A combination of a 5-point scale and 3-point Likert scale was used to assess the resident population's noise annoyance and the potential health impacts. The results revealed that the majority of the measured points have noise levels (55.71–65.24 LAeq dBA) exceeding both Oman and WHO critical limits. There was a general decrease in noise levels at points further away from the runways; thus, at points 2.5, 4.8, and 8.8 km, sound pressure levels were found to be 63.08, 57.41, and 52.31 dBA, respectively. However, steady noise levels were observed throughout most of the daily (24 h) measurements indicating continual exposures. Overall, 44.6% of residents reported noise annoyance level as very high, with Al Seeb inhabitants (46%) eliciting a greater percentage of annoyance levels compared to Bawshar (5%) due to their closer proximity to the airport. Also, the noise was significantly (p ˂ 0.001) associated with sleep disturbance, insomnia, irritation, and frightening. The majority of the residents complained of an increase in insomnia (41.5%), stress (34.3%), headache (47.3%), and cardiovascular diseases (16.2%). With the question of reducing noise exposures, about 41% of the respondents have plans of relocating to distant areas with low noise levels. [ABSTRACT FROM AUTHOR]

Historically, the dynamic testing of concrete dams has been associated with experimental modal analysis (EMA) and the performance of forced vibrations tests. Nevertheless, this type of tests requires the use of a heavy equipment and the interruption of the regular operation of the structure. An alternative to EMA relies on the application of operational modal analysis (OMA), through the performance of ambient vibration tests, and thus, it is essential to investigate if the application of OMA to concrete dams can provide good results with high levels of accuracy. In this context, this work addresses the performance of ambient vibration tests on concrete dams with quite diverse geometrical attributes and on the application of state-of-art output-only modal identification methods, to gain awareness of the issues that may occur during the application of OMA methods to signals with such low amplitudes (of the order of micro g), such as those that are usually recorded when dealing with these massive structures. More specifically, the paper describes the ambient vibration tests executed on six very different concrete dams. The most relevant modal properties are estimated through the application of modern output-only modal identification techniques, stressing the good level of accuracy achieved, which is quantified through the calculation of modal properties' uncertainties. Finally, a novel approach considering the uncertainties estimated is used to study the effect of noise on the quality of modal estimates and to qualify the adequacy of sensors to perform these tests on dams. [ABSTRACT FROM AUTHOR]

Abstract A recent work by Kimura et al. (Earth Planets Space 71:27, 2019. https://doi.org/10.1186/s40623-019-1006-x) (hereafter referred to as K19) claims to provide the first observational constraints on the prompt elastogravity signals (PEGS) induced by an earthquake. To make their claim, the authors argue that the observations shown in Vallée et al. (Science 358:1164–1168, 2017. https://doi.org/10.1126/science.aao0746) (hereafter referred to as V17) are spurious and their modeling inaccurate. Here we show that K19’s claim is invalid because it is based on flawed data processing. In fact, K19’s analysis involves an incomplete correction of the instrument response of broadband seismic sensors, which essentially dismisses low-frequency components of the data that are critical for the detection of intrinsically low-frequency signals such as PEGS. As a direct consequence, signals are much more difficult to observe than in V17, where the low part of the signal spectrum is carefully taken into account. This deficient data processing also explains why the signal amplitude reported by K19 after stacking data from multiple stations is lower than the individual signals reported by V17. Moreover, failing to take appropriate measures of data quality control, K19 used signals from low-quality sensors to call into question the signals detected by high-quality sensors. Finally, K19 use an inadequate simulation approach to model PEGS, in which the important effect of the ground acceleration induced by gravity changes is ignored. In summary, K19 do not show any viable arguments to question the observations and modeling of PEGS presented in V17.

Continuous time series data from geomagnetic observatories are increasingly contaminated by anthropogenic noise related to developing socio-economic activities. More and more sophisticated techniques of data processing are used to eliminate this noise; nonetheless, some of it cannot be removed. The main sources of noise in the Hyderabad (HYB) data are vehicular traffic, power lines and a power station, 500 m to 1 km away. During the nationwide COVID-19 pandemic lockdown from 24 March to 17 May 2020, both road and metro rail traffic came to a complete halt. The data from this time interval give us an opportunity to evaluate the effects of the absence of traffic-generated noise sources. We found noticeable differences in the noise levels present in vector and scalar variation data, due to the vehicular noise observed before and during the lockdown periods. Noise spectrum estimates quantify the reduction in the noise levels during this period. We also noticed decreased scatter in absolute values of the H (horizontal), D (declination), Z (vertical) and I (inclination) components of the geomagnetic field during lockdown. The details of increased data quality in the absence of traffic-generated noise sources are discussed.

The experimental results of th e noise spectra in the floating crane cabins under the sound radiation of the IC e ngine power - plant are presented. The frequency ranges when noise levels in the cabins exceed the sanitary norms are shown.

The theoretical studies on noise levels under hardening the surface layers of the helicopter spar pipes through the centrifugal processing are resulted. Spar is considered as a two-point article subjected to the periodic impulse force impact. The calculated relation is obtained for detecting the sound pressure levels at the natural frequencies. The reduced formulas include the geometric, mechanical characteristics, and the hardening processing methods which are set by the amplitude, duration, and impact momentum frequency. It allows determining the noise levels under the centrifugal processing including the design parameters of pieces and the processing conditions. On this basis, the noise level increase values as compared to the admissible limit values in the respective frequency ranges are calculated. This data is essential for the selection and acoustic design of the noise protection at the design stage of the centrifugal processing equipment.

The bilateral filter is a classical technique for edge‐preserving smoothing. It has been widely used as an effective image denoising approach to remove Gaussian noise. The performance of bilateral filtering highly depends on the accuracy of its range distance estimation, which is used for pixel‐neighbourhood similarity measurement. However, in the conventional bilateral filtering approach, estimating the range distance directly from noisy observation results in the degradation of denoising performance. To address this issue, the authors propose a novel bilateral filtering scheme with a dual‐range kernel, which provides a more robust range of distance estimation at various noise levels compared with existing methods. To further improve the denoising performance, they employ a linear model to retrieve the remaining image details from the method noise and add them back to the denoised image by employing an optimal approach based on Stein's unbiased risk estimate. Experiments on standard test images demonstrate that the proposed method outperforms conventional bilateral filter and its major state‐of‐the‐art variants. [ABSTRACT FROM AUTHOR]

This descriptive, cross‐sectional study in hospital ORs in İzmir, Turkey, assessed the environmental and physical ergonomic conditions that may place perioperative personnel at risk for injury or illness. We used an ergonomic conditions and risk factor description form to collect data in 58 ORs in nine different hospitals. We identified that the noise level and general air quality in the ORs were within recommended levels. However, none of the ORs had a surgical smoke evacuation system, pressure‐absorbing mats, or special equipment to facilitate patient moving and lifting. Approximately 70% of the ORs had high stools to provide short periods of rest for the surgical personnel. In addition, perioperative personnel did not wear protection to prevent intraoperative radiation exposure. These results indicate that although some environmental factors were within acceptable limits, other physical ergonomic risks were not adequately addressed, thereby placing perioperative staff members at risk for health concerns. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the sound intensity levels of a university-based wellness center. This research was initiated in response to the explosion of wellness centers being renovated and constructed across the nation at the university level and the need to entertain participants during fitness activities with some type of auditory sound. Measurements were taken in the wellness center under three conditions: quiet, music on, and music on/active. The intensity levels varied depending on the condition. Although the sound intensity was at an acceptable level during the quiet and music on condition, intensity levels reached an unacceptable level during the music on/active condition when not controlled by an administrator. This study provides a heightened awareness of the risks of possible hearing loss and promotes a role for professionals in health and human performance to collaborate with professionals in communication disorders in setting a safe intensity level of all audio systems. [ABSTRACT FROM AUTHOR]

Introduction: Background noise affects the listening environment inside classrooms, especially for younger children. High background noise level adversely affects not only student speech perception but also teacher vocal hygiene. The current study aimed to give an overview of the classroom listening conditions in selected government primary schools in India. Materials and Methods: Noise measurements were taken in 23 classrooms of four government primary schools in southern India, using a type 2 sound level meter. In each classroom measurements were taken in occupied and unoccupied conditions. Teacher voice level was measured in the same classrooms. In addition, the classroom acoustical conditions were observed and the reverberation time for each classroom was calculated. Results: The mean occupied noise level was 62.1 dBA and 65.6 dBC, and the mean unoccupied level was 62.2 dBA and 65 dBC. The mean unamplified teacher speech-to-noise ratio was 10.6 dBA. Both the occupied and unoccupied noise levels exceeded national and international recommended levels and the teacher speech-to-noise ratio was also found to be inadequate in most classrooms. The estimated reverberation time in all classrooms was greater than 2.6 seconds, which is almost double the duration of accepted standards. In addition, observation of classrooms revealed insufficient acoustical treatment to effectively reduce internal and external noise and minimize reverberation. Conclusion: The results of this study point out the need to improve the listening environment for children in government primary schools in India.

The research objective is to study the development of the noise spectra patterns in the operating area of copy mill operators. The experimental studies have shown that among harmful factors specific to these machines, there is an octave sound pressure level increase up to 15 dB in the idle mode and up to 15 dB under woodworking. These data suggest that the main noise source creating excess over the maximum permissible values is a spindle unit, and in particular, the spindle case. The vibration measurements on the machine carrier system have confirmed the results of the noise monitoring. The main source of the increased vibration levels for these machine tools is spindle rolling-contact bearings.

Visual observations of the marine biodiversity can be difficult in specific areas for different reasons, including weather conditions or a lack of observers. In such conditions, passive acoustics represents a potential alternative approach. The objective of this work is to demonstrate how information about marine biodiversity can be obtained via detailed analysis of the underwater acoustic environment. This paper presents the first analysis of the Saint-Pierre-and-Miquelon (SPM) archipelago underwater acoustic environment. In order to have a better knowledge about the marine biodiversity of SPM, acoustic recordings were sampled at different time periods to highlight seasonal variations over several years. To extract information from these acoustic recordings, standard soundscape and ecoacoustic analysis workflow was used to compute acoustic metrics such as power spectral density, third-octave levels, acoustic complexity index, and sound pressure levels. The SPM marine acoustic environment can be divided into three main sound source classes: biophony, anthrophony, and geophony. Several cetacean species were encountered in the audio recordings including sperm whales (which were detected by visual observations and strandings of 3 males in 2014), humpback, and blue whales.

Abstract One of the major environmental problems in contemporary societies is noise pollution, as it is well-known that noise adversely affects both the physiological and the psychological human health and well-being. This paper presents the development of Strategic Noise Maps and Action Plans for the "agglomeration of Piraeus", an area with >15% of the total population and almost 12% of the total area of the "Athenian – Piraeus conurbation". In Piraeus different noise sources, such as the railway, port activities, the road network, industrial and logistic activities etc., in combination with mixed land uses, dense urban canopy characteristics, residential areas adjacent to major road arterials etc. create a complicated noise environment that causes annoyance to the population. For this study, a campaign of 55 24-hour noise measurements was carried out and a series of 200 traffic counts were used for the estimation of traffic characteristics. Annual road traffic data were derived from a validated traffic model, while vessel, rail and industrial activity data were obtained from the service operators and in-situ surveys. The aforementioned noise/traffic measurements were used to calibrate a complex geographical model of the urban canopy and the noise sources layout. Strategic Noise Maps were then developed, along with estimations of the population exposure and DALYs lost from environmental noise per source. Action Plans including intervention measures aiming at the reduction of noise pollution in the area were then proposed. It was found that when implementing the interventions proposed both the noise levels and the exposure of population were significantly reduced, highlighting the importance of exposure reduction, especially for the vulnerable subpopulations, through prevention measures and strategies. Graphical abstract Unlabelled Image Highlights • Strategic Noise Maps and Action Plan for the agglomeration of Piraeus are presented. • The population exposure and DALYs lost were calculated per noise source. • The road traffic noise was found to dominate the noise profiles in the area. • Rail traffic and industrial noise are other important noise sources in the area. • Interventions significantly reduce the noise levels and the population exposure. [ABSTRACT FROM AUTHOR]

The detection of zero‐crossing (ZC) points in several power system applications, such as power conversion, grid synchronisation, power conditioning, and power system automation and control, is important toward ensuring a consistent performance even when there is variation in the supply frequency. However, the state‐of‐the‐art techniques of ZC detection are not very accurate in the presence of noise and harmonic distortions. This study introduces the concept of a support vector machine (SVM) in this context and subsequently proposes a robust SVM‐based ZC detection technique that addresses the aforementioned limitations. The simulation results show that the proposed technique obtains accurate values in the presence of transients, noise levels of up to 20%, and harmonic distortions of up to 50%. The experimental results provide similar observations. [ABSTRACT FROM AUTHOR]

This study is related to distribution temperature sensing (DTS) in sewers for tracing illicit or unintended inflows to foul sewers. A DTS measurement is performed with a fiber optic cable that is installed at the invert of a sewer pipe in combination with a standalone laser/computer instrument. This set-up generates in-sewer temperature measurements with high resolutions in time (every minute) and space (every metre) along the cable over long periods of time (weeks on end). The prolonged monitoring period in combination with the high level of detail in the dataset allows the study of anomalies (i.e., unexpected temperatures and/or temperature variations at certain locations), even if these only occur very infrequently. The objective of this paper is to develop an automated tool to analyze the large data masses and identify anomalies caused by illicit or unintended inflows. In this study, an algorithm for detecting the temperature changes that are caused by both wastewater discharge and inflow of stormwater are developed. A comparison of the results of the automated procedure to the results of a manual assessment of the datasets (Elmehaven, Denmark) shows that the automated procedure performs very well. [ABSTRACT FROM AUTHOR]

This paper presents the estimated residuals for detecting the traveling wave front using an adaptive extended Kalman filter based on the maximum likelihood (EKF‐ML), which uses the maximum likelihood method to adaptively optimize the error covariance matrices and the initial conditions. In some situations, such as faults close to the bus or close to zero inception angle, or faults with high fault resistances, the transient waves can become weak and even become lost in the noise, which makes the discrimination of the traveling wave front become more difficult. Aiming at this, residuals between the observed values and the estimated values using the adaptive EKF exhibit remarkable singularities, and can be used for exactly determining the wave front. Thus, the exact arrival time of the initial wave head can be determined and then the fault distance can be calculated precisely. The effectiveness of exacting mutation feature using the proposed method has been demonstrated by a simulated instantaneous pulse. And it has been tested with different types of faults using ATP simulation. Simulation results verify that the estimated residuals are highly sensitive to traveling wave front and less sensitive to modeling uncertainty (such as noise disturbance). [ABSTRACT FROM AUTHOR]

The growing demand for renewable energy supply stimulates a drastic increase in the deployment rate of offshore wind energy. Offshore wind power generators are usually supported by large foundation piles that are driven into the seabed with hydraulic impact hammers or vibratory devices. The pile installation process, which is key to the construction of every new wind farm, is hindered by a serious by-product: the underwater noise pollution. This paper presents a comprehensive review of the state-of-the-art computational methods to predict the underwater noise emission by the installation of foundation piles offshore including the available noise mitigation strategies. Future challenges in the field are identified under the prism of the ever-increasing size of wind turbines and the emerging pile driving technologies.

The aim of this work is to find the methods of reducing noise and vibration in the belt drive of the electromechanical drive of the selected technological equipment. Thus, we are having more comfortable working conditions in the workplace in compliance with the sanitary standards of noise and vibration. The noise abatement techniques and the simulation of the vibration of the grinding woodworker flexible gearing are considered. Modeling was performed with the introduction of Euler variables. The simulated dependences allow by calculation determine noise levels and load characteristics of the selected equipment. The comparison between the expected noise levels and the sanitary standards allow determining the exceedance and the sources of its generation. All this is the basis for selecting the engineering solutions to observe the noise code.

Since July 2015 a Superconducting Gravimeter (SG) of the latest generation, the iOSG-24, has been recording continuously the time-varying gravity field at the low noise underground laboratory (LSBB URL) of Rustrel, France. This instrument designed for observatory purpose has a levitated Niobium sphere weighting 17.7 g instead of 4.3 g. The advantage of increasing the mass of the sphere is to reduce the thermal noise due to Brownian motion inside the sensor. A comparison of the noise levels shows that the combination of this iOSG-24 with the environmental condition at the LSBB makes this site one of the quietest worldwide SG sites. Parallel measurements with an absolute FG5 gravimeter give a calibration factor of −451 ± 3 nm/s 2 /V and a negligible linear drift is observed 3 months after the installation. Tidal analyses are consistent with theoretical predictions and have shown a strong S1 thermal wave. Influence of the hydrological water content, mostly related to the Fontaine de Vaucluse catchment, is clearly visible on the SG residuals after tides removal. However the hydrological influence modelled using the MERRA2 products does not fully explain the observed noise level at periods between 1 and 10 days. Longer gravimetric time-series are necessary to further study the seasonal hydrological effects. [ABSTRACT FROM AUTHOR]

Background Preterm infants usually have to spend a long time in an incubator, excessive noise in which can have adverse physiological and psychological effects on neonates. In fact, incubator noise levels typically range from 45 to 70 dB but differences in this respect depend largely on the noise measuring method used. The primary aim of this work was to assess the extent to which noise in an incubator comes from its own fan and how efficiently the incubator can isolate external noise. Methods Three different incubator models were characterized for acoustic performance by measuring their internal noise levels in an anechoic chamber, and also for noise isolation efficiency by using a pink noise source in combination with an internal and an external microphone that were connected to an SVAN958 noise analyzer. Results The incubators studied produced continuous equivalent noise levels of 53.5–58 dB and reduced external noise by 5.2–10.4 dB. Conclusions A preterm infant in an incubator is exposed to noise levels clearly exceeding international recommendations even though such levels usually comply with the limit set in the standard IEC60601-2-19: 2009 (60 dBA) under normal conditions of use. [ABSTRACT FROM AUTHOR]

Image denoising is still a challenging problem in image processing. The authors propose a novel image denoising method based on a deep convolution neural network (DCNN). Different from other learning‐based methods, the authors design a DCNN to achieve the noise image. Thus, the latent clear image can be achieved by separating the noise image from the contaminated image. At the training stage, the gradient clipping scheme is employed to prevent gradient explosions and enables the network to converge quickly. Experimental results demonstrate that the proposed denoising method can achieve a better performance compared with the state‐of‐the‐art denoising methods. Also, the results indicate that the denoising method has the ability of suppressing different noises with different noise levels by means of one single denoising model. [ABSTRACT FROM AUTHOR]

The road traffic is one of the main sources of noise pollution in the urban area. The main purpose of this study was to measure the ambient noise fluctuation levels in five selected sites of Dire Dawa city. The study reports traffic noise fluctuations during the day and night since the city is an industrial corridor and it is used as a dry port for the country. The noise level was measured after the standard measure followed by standard calibrated devices. The variations of the equivalent noise levels were represented in figures and the total annoyance of the noise levels was calculated and shown in Table 1. The results revealed that the highest annoyance and the equivalent noise levels at Delchora hospitals were 83.15 dB and 85.20 dB respectively in the morning. However, the noise pollution level (LNP) at Delchora Hospital during the morning is greater than in the afternoon. The minimum noise levels were measured in the residence of MA hotel 24.77 dB with the standard deviation of 0.10 in the morning time interval. [ABSTRACT FROM AUTHOR]

Due to the continuous developments in both science and technology, arises a high importance in organizing human activity at the workplace. Two of the most aggressive factors in the workplace are noise and vibration. The noise problem is quite prevalent today because there are a lot more jobs available in industries with a high level of hazard, and so is the number of exposed workers. The purpose of this paper is to analyze the noise and vibration levels in the pipes manufacturing process measured at SC Pipes SRL from Iasi. Following the field measurements taken in the factory, it has surfaced that in some sections, the noise level has exceeded the maximum level of exposure set in Government Decision (GD) 493/2006. Regarding the vibration exposure measurements, it was found that all measurements were within exposure levels set in (GD) 1876/2005. [ABSTRACT FROM AUTHOR]

• Visual cues has little effect on SI scores in higher SNR condiitons. • SI scores decrased by 10% at a SNR of 6 dBA or lower. • The benefit of acoustic and visual signals differs at different noise levels. Acoustical measurements and speech intelligibility tests were carried out to investigate the effects of masks on speech communication experienced in real Covid-secure university classrooms during the pandemic. Face-masked speech levels and noise levels were measured to understand the acoustical effects of masks on speech sounds during 15 multiple lectures in 3 university classrooms. The speech intelligibility scores were also evaluated for lower and higher SNR (signal-to-noise ratio) conditions, and for with and without the presence of visual information conditions to investigate the effects of both the acoustic and visual signals in understanding speech communication in actual classroom situations. In the 3 active university classrooms the students experienced on average: speech levels of 55.1 dBA (σ = 5.5 dBA), noise levels of 42.3 dBA (σ = 3.9 dBA), and a speech-to-noise ratio of 12.8 dBA σ = 5.2 dBA). The mean SNR values at the listener's position for the 15 lectures varied from 3.6 dBA to 20.0 dBA. The use of a portable sound amplification system increases the face-masked speech levels mostly at mid and high frequencies (500–4 kHz), thus it can be more useful for achieving higher SNR values in classrooms. The presence of visual cues have little effect on achieving more higher speech intelligibility scores in higher SNR conditions. The present results show that visual obstruction of the talker's mouth decreases speech intelligibility scores by a maximum of 10% in lower SNR conditions, particularly at a SNR of 6 dBA or lower. [ABSTRACT FROM AUTHOR]

The noise in the metro station is synthesized from a variety of different noise sources. Excessive noise exposure will bring serious impacts on humans' health. To alleviate the shortage of the urban land, most metro stations are planning to develop convenience stores and shopping malls. In order to evaluate the potential noise impact on humans' comfort in the metro stations, this study selected four representative stations of Guangzhou Metro Line 1 to carry out a preliminary questionnaire survey of 226 respondents for the perception and perform a noise measurement. Additionally, platform screen doors as a potential method for noise mitigation were examined. The results show that the noise caused by trains was dominant in the metro stations; however, the noise impact by public broadcast and passengers cannot be ignored. The noise levels of the transfer stations were obviously greater than the normal stations, especially during the peak hours. In addition, people in the metro stations have potential exposure to noise that the noise levels exceed the criteria limit of China, which would bring discomfort for humans; however, the normal activities of people would not be impacted. The platform screen doors should be further improved or relevant noise mitigation methods should be taken into account to reduce the noise level within the criteria limit. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to compare the noise levels recorded in two different neonatal intensive care unit (NICU) settings: a pod and an open plan NICU located in the same hospital. Background: The NICU is a busy environment with ambient noise levels that often exceed established recommendations. This noise deleteriously affects the physiological stability and developmental outcomes of sick and preterm infants. Pods have reduced numbers of cots (in this case, 6) compared to open plan NICUs (in this case, 11), yet the noise levels in pods have not been reported. Method: This study compared real-time decibel (dB) levels in an A-weighted scale, captured continuously by sound dosimeters mounted in both NICU settings for a period of 4 weeks: a pod setting and an open plan NICU. Researchers also collected observational data. Results: The average noise level recorded in the pod was 3 dBs less than in the open plan NICU. This result was statistically significant. However, dB recordings in both areas were over the recommended limits by 4-6 dBs, with isolated peaks between 74.5 dBs (NICU) and 75.9 dBs (pod). Observational data confirmed this correlation. Conclusions: Further research to evaluate interventions to decrease the noise levels in both settings are needed, especially during times of peak activity. Staff working in these settings need to be more aware that control of acoustic levels is important in the neuroprotection of neonates. Coupling this with careful consideration to structural components and evidence-based design planning may contribute to lowering dB levels in the NICU environment. [ABSTRACT FROM AUTHOR]