Equivalent Noise Level Research Articles

Miniature Three-Axis Induction Magnetometer for Borehole Logging

A miniature three-axis induction magnetometer (IM) for borehole logging was designed, manufactured, and tested. The form of the IM is a cube with 12 coils at edges, which are embedded in a ring cylinder. Thus, the 12 coils are placed along the x , y , and z axes. Each axis consists of four coils that are connected in series. The length, inner diameter, and outer diameter of the ring cylinder are 40, 43, and 64 mm, respectively. The mass of the IM is 450 g. The working frequency bandwidth is set within 1 Hz–10 kHz. The equivalent induction magnetic noise level of the IM is less than 10 pT/√Hz at 100 Hz for three axes. The features and the noise performances of the IM show the potential for its use in borehole logging.

EVALUATION OF NOISE POLLUTION INDICATORS IN NAJAF CITY

This study sheds light on measuring and calculating the average of noises pollution indications in An Najaf. The city has recently got growth in commercial and industrial activities as well as a significant increase in the number of vehicles. In addition, the use of diesel generators is due to electricity shortage for long periods. Noise quality assessment was studied in An Najaf City for five areas, i.e., educational, industrial, commercial, residential and quiet. The study has been conducted for five months starting in November 2016. Noise pollution indicators viz. L10, L50, L90, noise climate (N.C), equivalent continuous noise level (Leq) and noise pollution level (Lnp) were calculated for the above mentioned five areas. The results of this study showed that the highest value of (Leq), which is 108.44 dB, was in the industrial areas followed by 89.55 dB in the commercial areas, 87.1 dB in the educational areas, 80.4 dB in the quiet areas, and 69.05 dB in the residential areas. It has been noted that the highest values of Leq in all areas were higher than the permissible limit in the Iraqi standards, where the noise assessment study in this research revealed the disturbing situation of noise pollution in the city of Najaf.

Investigation of Additive Manufacturing for Broadband Choked Horns at X/Ku Band

Additive manufacturing is becoming a popular alternative to traditional manufacturing techniques as it has reached a suitable maturity and accuracy for microwave applications. The main advantage is that the manufacturing can be performed directly from the three-dimensional CAD model, available from the numerical simulation of the antenna, without significant modifications. This is a highly desirable feature, in particular for time and cost critical applications such as prototyping and manufacturing of small quantities of antennas. In this letter, we investigate accuracy and repeatability of selective laser melting manufacturing of fully metallic broadband chocked horns at X/Ku band. A complete batch of 15 antennas has been manufactured and validated in terms of matching, radiation efficiency, and volumetric radiation patterns throughout their operating bandwidth. Manufacturing accuracy and repeatability have been evaluated using RF parameters as performance indicators, comparing measured data and high-accuracy simulations. These indicators are compared to state-of-the-art values commonly found for traditional manufacturing. The radiation patterns have been correlated to the numerical reference using equivalent noise level as a performance indicator. For input matching, manufacturing repeatability has been quantified by defining an interference level.

Quiet areas and urban sustainability

About 0.62 million DALYs are lost yearly among the urban population in EU countries owing to the occurrence of noise annoyance. One of the appointed causes deals with the fact that urban areas are focus of sustainability strategies not considering the noise factor. As a matter of fact, natural resources, energy, economy, air quality among others, are usual environmental factors associated to sustainability studies but not noise. Because of the evolution of humanity, people are driven to live together in big (very big) urban spaces, where urban noise is usually the scope of acoustic studies in its physical aspects but rarely involving people reaction. It is the case of the reaction of users of Quiet Areas evaluated by noise maps and statistical parameters.The aim of this work is focused in the relationship between urban noise in “quiet areas” and human reaction as a beacon for urban sustainability. It is proposed the “quiet area reaction to noise - ANN” concept to promote areas in urban landscape where not only sound is related with nature, but also fauna and flora are representative of a men low impact intervention. International rules recommend that any citizen should not be farther from a quiet area than 30 walking min. ANN is proposed as an annoyance reaction correlation with Equivalent Noise Level [Lden, Ln]. The proposed concept is applied at Porto in two different cases of Quiet Areas, City Park and Covelo Farm, from where data is presented as an illustration of the concept. Conclusions allow understanding that noise maps based on Equivalent Noise Levels [Leq, Ln] are not suitable to identify people reaction in “Quiet Areas”. The proposed model is quite accurate for “none” and “highly” annoyance environments and further research is needed do better identify “moderate” and “little” annoyance.

Empirical Study of Room Acoustic Conditions and Neurophysiologic Strain in Staff Working in Special Open-Plan Bank Offices

Noise in open-plan offices induces psychological stress and fatigue in staff. Focusing on workstations and noise exposure, this study investigated acoustic conditions in special open-plan offices and their relationship with neurophysiologic strain. Twenty banks and 104 participants were randomly selected. Acoustic properties of banks and workstation partitions were assessed using the ISO criteria and speech transmission index (STI). Equivalent noise level (LAeq) of the staff was measured in three 30-min intervals, and skin conductance level (SCL) and respiratory rate (RR) of staff were assessed in three 5-min intervals at the beginning, in the middle, and at the end of the work hours. The intelligibility of speech between staff workstations (SW) was better than that between staff and clients (SC however, with increasing STI between SW and with decreasing STI between S&C, the staff strain increased. With increasing noise exposure, psychological stress of the staff increased too. Because of the acoustic condition and partitions used in the banks, the acoustic comfort of staff was not desirable. Since many other banks use such partitions, any improvement in partitions between workstations can enhance acoustic comfort in the banks.

Capturing the spatial variability of noise levels based on a short-term monitoring campaign and comparing noise surfaces against personal exposures collected through a panel study

Environmental noise can cause important cardiovascular effects, stress and sleep disturbance. The development of appropriate methods to estimate noise exposure within a single urban area remains a challenging task, due to the presence of various transportation noise sources (road, rail, and aircraft). In this study, we developed a land-use regression (LUR) approach using a Generalized Additive Model (GAM) for LAeq (equivalent noise level) to capture the spatial variability of noise levels in Toronto, Canada. Four different model formulations were proposed based on continuous 20-min noise measurements at 92 sites and a leave one out cross-validation (LOOCV). Models where coefficients for variables considered as noise sources were forced to be positive, led to the development of more realistic exposure surfaces. Three different measures were used to assess the models; adjusted R2 (0.44–0.64), deviance (51−72%) and Akaike information criterion (AIC) (469.2–434.6). When comparing exposures derived from the four approaches to personal exposures from a panel study, we observed that all approaches performed very similarly, with values for the Fractional mean bias (FB), normalized mean square error (NMSE), and normalized absolute difference (NAD) very close to 0. Finally, we compared the noise surfaces with data collected from a previous campaign consisting of 1-week measurements at 200 fixed sites in Toronto and observed that the strongest correlations occurred between our predictions and measured noise levels along major roads and highway collectors. Our validation against long-term measurements and panel data demonstrates that manual modifications brought to the models were able to reduce bias in model predictions and achieve a wider range of exposures, comparable with measurement data.

Estimation of the quality of an urban acoustic environment based on traffic noise evaluation models

Traffic noise pollution is a widespread public health problem in both developing and developed countries. Quickly and effectively evaluating the quality of an urban acoustic environment is an important challenge for urban planning and management. To solve this problem, this study first classified the urban function area of the study area according to the functional characteristics and environmental quality requirements of the region, and then, the traffic noise propagation model was applied to predict instantaneous sound levels (LA) based on noise attenuation. Finally, a traffic noise evaluation model was proposed to evaluate the quality of the urban acoustic environment. Taking Changchun city as our study area, eighty field samples of equivalent noise levels (Leq) were measured every ten minutes at four types of roads, classified as trunk roads, secondary roads, expressways and rural roads, in different urban function areas. An urban noise map was drawn to reflect the degree of traffic noise pollution. By comparing the measured and predicted values of noise levels, the results show that the traffic noise propagation model can be used to predict instantaneous sound levels. The traffic noise evaluation results show that the quality of the acoustic environment in our study area was at a medium level, which means that long-term exposure to it can affect the normal work and life of people. The traffic noise propagation model and proposed evaluation model are feasible methods for evaluating the quality of the acoustic environment and can provide a reference for the management of noise pollution control of urban traffic.

Detection of Anomalous Noise Events for Real-Time Road-Traffic Noise Mapping: The Dynamap’s project case study

Abstract Environmental noise is increasing year after year, especially in urban and suburban areas. Besides annoyance, environmental noise also causes harmful health effects on people. The Environmental Noise Directive 2002/49/EC (END) is the main instrument of the European Union to identify and combat noise pollution, followed by the CNOSSOS-EU methodological framework. In compliance with the END legislation, the European Member States are required to publish noise maps and action plans every five years. The emergence of Wireless Acoustic Sensor Networks (WASNs) have changed the paradigm to address the END regulatory requirements, allowing the dynamic ubiquitous measurement of environmental noise pollution. Following the END, the LIFE DYNAMAP project aims to develop a WASN-based low-cost noise mapping system to monitor the acoustic impact of road infrastructures in real time. Those acoustic events unrelated to regular traffic noise should be removed from the equivalent noise level calculations to avoid biasing the noise map generation. This work describes the different approaches developed within the DYNAMAP project to implement an Anomalous Noise Event Detector on the low-cost sensors of the network, considering both synthetic and real-life acoustic data.Moreover, the paper reflects on several open challenges, discussing how to tackle them for the future deployment of WASN-based noise monitoring systems in real-life operating conditions.

Pathways linking residential noise and air pollution to mental ill-health in young adults

BackgroundRecent years have seen growing, but still tentative, evidence of the potential associations of environmental noise and air pollution with mental disorders. In the present study, we aimed to examine the associations between residential noise and air pollution exposures and general mental health in young adults with a focus on underlying processes MethodsWe sampled 720 students (18–35 years) from one university in the city of Plovdiv, Bulgaria. Residential noise (LAeq; day equivalent noise level) and air pollution (NO2) were assessed at participant's residential address by land use regression models. General mental health was measured with a short form of the General Health Questionnaire (GHQ). The following putative mediators were considered: annoyance from environmental pollution, sleep disturbance, restorative quality of the neighborhood, neighborhood social cohesion, and commuting/leisure time physical activity. Structural equation modeling was used to analyze the theoretically-indicated interplay between exposures, mediators, and GHQ. ResultsWe observed an association between higher LAeq and GHQ, in which environmental annoyance and neighborhood restorative quality emerged as key mediators. First, LAeq was associated with higher annoyance, and through it with lower restorative quality, and then in turn with lower physical activity, and thus with higher GHQ. Simultaneously, higher annoyance was associated with higher sleep disturbance, and thereby with higher GHQ. NO2 had no overall association with GHQ, but it was indirectly associated with it through higher annoyance, lower restorative quality, and lower physical activity working in serial. ConclusionWe found evidence that increased residential noise was related to mental ill-health through several indirect pathways. Air pollution was associated with mental health only indirectly.

SANITARY-HYGIENIC CHARACTERISTIC OF WORKING CONDITIONS AND STATE OF HEALTH OF TEACHERS

Relevance. The main causes, which cause voice disruption in teachers can be divided into biological, professional, everyday, psychological. Combinations of two or more factors are possible. Objective. To carry out an analysis of working conditions and the state of health of teachers of general educational institutions in the city of Krivoy Rog.Materials and methods. The analysis of working conditions is carried out sanitary-hygienic method. The state of health of teachers is investigated by a clinical method.
 Results. The working conditions of teachers are characterized as tense and heavy, and in terms of labor intensity indicators belong to class 3.3, microclimate and equivalent noise level to class 3.1. Chronic catarrhal laryngitis is 131,00±15,07 cases, hypertrophic laryngitis – 190,20±22,61 cases. The critical work experience under the conditions of the impact of the voice load is 10-19 years, accounting for 60 % of cases of professional laryngitis.
 Conclusions. Analysis of working conditions, the duration of the voice load and the levels of the pathology of the vocal apparatus open up prospects for determining the risk of developing professional laryngitis in teachers and developing modern methods of treatment and prevention.

SANITARY-HYGIENIC CHARACTERISTIC OF WORKING CONDITIONS AND STATE OF HEALTH OF TEACHERS

Relevance. The main causes, which cause voice disruption in teachers can be divided into biological, professional, everyday, psychological. Combinations of two or more factors are possible. Objective. To carry out an analysis of working conditions and the state of health of teachers of general educational institutions in the city of Krivoy Rog.Materials and methods. The analysis of working conditions is carried out sanitary-hygienic method. The state of health of teachers is investigated by a clinical method. Results. The working conditions of teachers are characterized as tense and heavy, and in terms of labor intensity indicators belong to class 3.3, microclimate and equivalent noise level to class 3.1. Chronic catarrhal laryngitis is 131,00±15,07 cases, hypertrophic laryngitis – 190,20±22,61 cases. The critical work experience under the conditions of the impact of the voice load is 10-19 years, accounting for 60 % of cases of professional laryngitis. Conclusions. Analysis of working conditions, the duration of the voice load and the levels of the pathology of the vocal apparatus open up prospects for determining the risk of developing professional laryngitis in teachers and developing modern methods of treatment and prevention.

A SKIROC2-based prototype electronics system for silicon PIN array

Silicon PIN (Si-PIN) diode has been widely used in high-energy physics experiments. The next-generation experiments ask for a large amount of the Si-PIN diode arrays, leading to a requirement for the electronics system with features of higher integration and lower power consumption than the traditional ones. The aim was to design and implement a prototype of multi-channel electronic system, which is based on the SKIROC2 ASIC. The system is also considered as the pre-research of the silicon–tungsten (Si-W) ECAL for CEPC. The prototype is divided into two parts, so that it has the potentiality for the expansion of more readout channels. The front-end board (FEB), which carries a Si-PIN diode array and an ASIC of SKIROC2 on it, provides high voltage to the Si-PIN diodes and processes the signals as well. The FEB is configured by a data interface board (DIF) and sends data to the DIF, which then transfers data to PC via USB interface after packing process. The prototype electronics system has been implemented. The equivalent noise level of all the 64 channels is below 0.4 fC. The dynamic range is up to +3000 fC with an integral nonlinearity (INL) of 0.2 %, and the gain non-uniformity is better than 5 %. The energy resolution with 59 keV X-rays from 241Am is about 13.3 % (in RMS), while the signal-to-noise ratio (SNR) reaches about 10.9 for minimum ionizing particles (MIPs). In this paper, a SKIROC2-based prototype electronics system for Si-PIN array, as well as the performance test, has been presented. The system has features of high integration, low noise, and high dynamic range. The SKIROC2, as well as the design concept of the electronics system, can be applied to the preliminary prototype Si-W ECAL of CEPC.

Investigation of occupational noise annoyance in a wind turbine power plant

Noise, emitted by wind turbines, is one of the main health risk factors which has been recently considered in many researches. Noise annoyance is among the most important human responses to noise. The aim of this work was to modeling of annoyance due to noise at workplace coming from wind turbines in workers. All workers of a wind power plant consisted the study sample. The equivalent noise level was measured using a task-based method. Moreover, data related to noise annoyance and noise sensitivity were acquired by standardized methods. Based on the results, noise exposure, noise sensitivity, visibility, age, and experience affected noise annoyance. According to path analysis, the most indirect and direct effect on noise annoyance were attributed to noise exposure. Age, sensitivity, and noise exposure were positively associated to annoyance. It can be concluded that there is a significant relationship between age, experience, sensitivity to noise, and exposure to the wind turbine noise with noise annoyance.

Analysis on hearing status and related influencing factors in workers exposed to noise in an automobile manufacture enterprise

Objective: To study the hearing status and analyze the related influencing factors in noise-exposed workers in an automobile manufacture enterprise, and put forward suggestions for prevention of noise-induced hearing loss. Methods: Noise exposure level testing, audiometry testing and questionnaires were performed for noise exposed workers in the automobile manufacture enterprise. To analyze the relationship between different factors and noise-induced hearing loss by cumulative noise exposure(CNE) calculated 8-hour continuous A-weighted equivalent noise level and seniority. Results: The detection rate of hearing loss in noise-exposed workers was 22.8%. The noise exposure intensity of stamping workshop is higher than other workshop, and the hearing loss detection rate of stamping workshop workers is higher than other workshop workers. The detection rate of hearing loss has significant difference in L(Aeq·8 h), seniority, CNE, age, high temperature and wearing earplugs (P<0.05). The results of logistic regression analysis showed that CNE, age and high-temperature were risk factors for noise-induced hearing loss (P<0.05 and OR>1) and there was an increasing tendency of hearing loss with increase in length of service and CNE, while using of earplugs was a protective factor (P<0.05 and OR<1). With the increase of CNE, the incidence of hearing loss is the rising trend. Conclusion: It is suggested to strengthen the noise control and individual protection and improve the high-temperature working environment, which plays an important role in reducing the occurrence of noise-induced hearing loss.

Noise level in neonatal incubators: A comparative study of three models

BackgroundPreterm 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. MethodsThree 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. ResultsThe incubators studied produced continuous equivalent noise levels of 53.5–58 dB and reduced external noise by 5.2–10.4 dB. ConclusionsA 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.

Patients with visual "snow" have normal equivalent input noise levels.

Patients with visual "snow" have normal equivalent input noise levels.

On the Impact of Anomalous Noise Events on Road Traffic Noise Mapping in Urban and Suburban Environments.

Noise pollution is a critical factor affecting public health, the relationship between road traffic noise (RTN) and several diseases in urban areas being especially disturbing. The Environmental Noise Directive 2002/49/EC and the CNOSSOS-EU framework are the main instruments of the European Union to identify and combat noise pollution, requiring Member States to compose and publish noise maps and noise management action plans every five years. Nowadays, the noise maps are starting to be tailored by means of Wireless Acoustic Sensor Networks (WASN). In order to exclusively monitor the impact of RTN on the well-being of citizens through WASN-based approaches, those noise sources unrelated to RTN denoted as Anomalous Noise Events (ANEs) should be removed from the noise map generation. This paper introduces an analysis methodology considering both Signal-to-Noise Ratio (SNR) and duration of ANEs to evaluate their impact on the A-weighted equivalent RTN level calculation for different integration times. The experiments conducted on 9 h of real-life data from the WASN-based DYNAMAP project show that both individual high-impact events and aggregated medium-impact events bias significantly the equivalent noise levels of the RTN map, making any derived study about public health impact inaccurate.

Um panorama dos níveis de ruído para conforto acústico de ambientes de ensino com vdt em áreas das regiões brasileiras

As instituições de ensino têm papel fundamental na formação dos indivíduos, influenciando direta e indiretamente em questões sociais, econômicas e ambientais. Dentre os problemas de conforto ambiental mais encontrados em ambientes de ensino, destacam-se os excessivos níveis de ruído, que afetam o processo de ensino-aprendizagem. O objetivo deste trabalho é avaliar os parâmetros de níveis de ruído de seis laboratórios de informática com Video Display Terminals (VDTs) de Centros de Tecnologia de Instituições de Ensino Superior (IES) em áreas das regiões brasileiras, avaliando o comportamento e a conformidade do seu nível de ruído equivalente (LAeq) e elaborando um modelo matemático que compare os níveis de ruído entre as instituições. A conformidade dos níveis de ruído foi avaliada segundo a NBR 10152/1987, a ANSI S12.60-2002 e as diretrizes da Organização Mundial da Saúde. O estudo se trata de uma pesquisa experimental, cujas medições técnicas foram realizadas de acordo com a NBR 10151/2000. A análise descritiva mostrou que os seis ambientes de ensino avaliados apresentaram LAeq superiores aos valores estabelecidos nas normas aplicáveis. Criou-se um modelo linear generalizado para comparar os níveis de ruído entre os laboratórios das instituições, que corroborou os resultados obtidos na análise descritiva. Avaliaram-se os aspectos arquitetônicos dos laboratórios e concluiu-se que os elevados níveis de ruído podem estar vinculados aos baixos coeficientes de absorção dos materiais presentes nessas salas. A originalidade está na análise das diferenças dos níveis de ruídos entre os laboratórios a partir de uma modelagem matemática, mas levando-se em consideração os aspectos arquitetônicos.

Analysis of possible factors of vocal interference during the teaching activity.

ABSTRACTOBJECTIVETo measure the risk of dysphonia in teachers, as well as investigate whether the perceptual-auditory and acoustic aspects of the voice of teachers in situations of silence and noise, the signal-to-noise ratio, and the noise levels in the classroom are associated with the presence of dysphonia.METHODSThis is an observational cross-sectional research with 23 primary and secondary school teachers from a private school in the municipality of São Paulo, Brazil, divided into the groups without dysphonia and with dysphonia. We performed the following procedures: general Dysphonia Risk Screening Protocol (General-DRSP) and complementary to speaking voice - teacher (Specific-DRSP), voice recording during class and in an individual situation in a silent room, and measurement of the signal-to-noise ratio and noise levels of classrooms.RESULTSWe have found differences between groups regarding physical activity (General-DRSP) and particularities of the profession (Specific-DRSP), as well as in all aspects of the perceptual-auditory vocal analysis. We have found signs of voice wear in the group without dysphonia. Regarding the vocal resources in the situations of noise and silence, we have identified a difference for the production of abrupt vocal attack and the tendency of a more precise speech in the situation of noise. Both the signal-to-noise ratio and the room noise levels during class were high in both groups.CONCLUSIONSTeachers in both groups are at high risk for developing dysphonia and have negative vocal signals to a greater or lesser extent. Signal-to-noise ratio was inadequate in most classrooms, considering the standards for both children with normal hearing and with hearing loss, as well as equivalent noise levels.

Study of the Low-Frequency Excess Equivalent Magnetic Noise in GMI-Based Devices

Low-frequency equivalent magnetic noise levels of four different giant magneto-impedance (GMI) samples, exhibiting $1/f$ spectral behavior, have been experimentally determined, for several excitation conditions (involving both dc current and ac excitation amplitude). Under appropriate conditions, for which the noise level at 1 Hz is minimal, coherence measurements show that the main noise source responsible for this low frequency noise is the intrinsic noise of the GMI sample. The lowest corresponding magnetic noise performances of the four samples were determined. The lowest noise level observed was $17\,\textrm {pT}/(\textrm {Hz})^{1/2}$ at 1 Hz. It has been proposed that the imaginary part of the magnetic susceptibility, $\chi ^{\prime \prime }$ , a measure of the low frequency magnetization fluctuations, determines the resulting magnetic noise level of the sensor. Its values at 1 Hz have been been evaluated for all four samples. Using these evaluations, expected noise levels at 1 Hz are computed, based on a previously proposed theoretical model, and compared with the measured noise performances. Under conditions for which correlation measurements show that system noise is dominated by sensor noise, the two sets of values are in reasonably good agreement, suggesting that the proposed model for low frequency excess noise of GMI materials is essentially correct.