Comparison of noise-levels between superconducting gravimeter and gPhone gravimeter

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The relationship between age,acceptable noise level,and listening effort in middle-aged and older-aged individuals

Objective:The purpose of the study was to evaluate listening effort in adults who experience varied annoyance towards noise.Materials and methods:Fifty native Kannada-speaking adults aged 41e68 years participated.We evaluated the participant's acceptable noise level while listening to speech.Further,a sentence-final wordidentification and recall test at 0 dB SNR(less favorable condition)and 4 dB SNR(relatively favorable condition)was used to assess listening effort.The repeat and recall scores were obtained for each condition.Results:The regression model revealed that the listening effort increased by 0.6%at 0 dB SNR and by 0.5%at 4 dB SNR with every one-year advancement in age.Listening effort increased by 0.9%at 0 dB SNR and by 0.7%at 4 dB SNR with every one dB change in the value of Acceptable Noise Level(ANL).At 0 dB SNR and 4 dB SNR,a moderate and mild negative correlation was noted respectively between listening effort and annoyance towards noise when the factor age was controlled.Conclusion:Listening effort increases with age,and its effect is more in less favorable than in relatively favorable conditions.However,if the annoyance towards noise was controlled,the impact of age on listening effort was reduced.Listening effort correlated with the level of annoyance once the age effect was controlled.Furthermore,the listening effort was predicted from the ANL to a moderate degree.

A new approach of drawing airport noise contours on computer based on Surfer

Noise contours are used to describe the extent of airport noise pollution and to plan land use around airports. The L WECPN(weighted equivalent continuous perceive noise level) recommended by ICAO(International Civil Aviation Organization) is adopted as airport noise rating parameter in this paper. With the help of various mathematical models in the software Surfer, noise contours can be drawn automatically by the completed program in Visual C++ Code. Corrections for thrust, velocity, atmospheric temperature, humidity and lateral ground attenuation are also considered in the new method, which can improve the efficiency of drawing contours. An example of its use for drawing noise contours of an airport in Zhejiang Province of China is proposed and the predictions and the measurements show agreements well.

Experimental and Numerical Study of the Key Non-Dimensional Geometrical Parameters on the Noise Level of Dry-Type Cast Resin Transformers

Dry-Type Cast Resin Distribution Transformers(CRT)is the secondgeneration of air-cooled distribution transformers where oil is replaced by resin for electrical insulation.CRT transformers may installed indoor adjacent to or near residential areas since they are clean and safe comparing to the conventional transformers.But,as it is obvious,noise discrepancy is intrinsically accompanied with all types of transformers and is inevitable for CRT transformers too.Minimization of noise level caused by such these transformers has biological and ergonomic importance.As it is known the core of transformers is the main source of the noise generation.In this paper,experimental and numerical investigation is implemented for a large number of fabricated CRT transformers in IT Co(Iran Transfo Company)to evaluate the effective geometrical parameters of the core on the overall sound level of transformers.Noise Level of each sample is measured according to criteria of IEC60651 and is reported in units of Decibel(dB).Numerical simulation is done using noncommercial version of ANSYS Workbench software to extract first six natural frequencies and mode shapes of CRT cores which is reported in units of Hz.Three novel non-dimensional variables for geometry of the transformer core are introduced.Both experimental and numerical results show approximately similar response to these variables.Correlation between natural frequencies and noise level is evaluated statistically.Pearson factor shows that there is a robust conjunction between first two natural frequencies and noise level of CRTs.Results show that noise level decreases as the two first natural frequencies increases and vice versa,noise level increases as the two natural frequencies of the core decreases.Finally the noise level decomposed to two parts.

Effects of geometric design of forest road and roadside vegetation on traffic noise reduction

Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car （Land Rover） relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type （coniferous and hardwood） in 40 rectangular plots of three widths （25, 100 and 300 m） and 50 m length that were randomly demar- cated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of q-1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30-45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % （67 dB） and 3-8 % （71.2 dB） in comparison with slopes greater than 8 % （77.8 dB）, （p 〈 0.05）. Pinus brutia L. reduced the noise level more （about 6 dB） in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.

The influence of observation environment on background noise level of gPhone gravimeter

Based on the observations of 36 gPhone gravimeters in 2015, the background noise levels in the seismic frequency band（200-600 s） and sub-seismic band（1-6 h） are calculated. The differences in the PSD（power spectrum density） of each band of gPhone gravimetric gauges in different surrounding environments were analyzed and compared with Peterson＇s NLNM（new low-noise model） which is derived from the envelope at the power spectrum density of 75 seismograph stations around the world. The results showed that： the influence of station type on the noise magnitude of gPhone gravimeter is very small; The seismic band noise magnitude（hereinafter referred to as SNM） and the sub-seismic band noise magnitude（hereinafter referred to as SSNM） in the coastal gPhone gravimeter are higher than those of inland stations. Although the local hydrological change has a great influence on the gravity observation, the rainfall is not directly relative to the noise magnitude of the instrument. Except 3 coastal stations, the eight stations which had the highest amplitudes in the SNM were located near the seismic belt. This indicates that the SNM of the gPhone Gravimeter may reflect some seismic information.Compared with the NLNM model, the PSD of the gPhone gravimeter is lower than the NLNM model in the long period band（〈3×10^（-5）Hz）, indicating that the gPhone gravimeter is more suitable for detecting long-period signals（〉10 h） than the seismometer.

Sequential Filtering for Surface Wind Speed Estimation from Ambient Noise Measurement

Many research results show that ocean ambient noise and wind speed are highly relevant, and the surface wind speed can be effectively inverted using ocean noise data. In most deep-sea cases, the ambient noise of medium frequency is mainly determined by the surface wind, and there is a conventional relationship between them. This paper gives an equation which shows this relationship firstly, and then a surface-wind inversion method is proposed. An efficient particle filter is used to estimate the speed distribution, and the results exhibit more focused close to the actual wind speed. The method is verified by the measured noise data, and analysis results showed that this approach can accurately give the trend of sea surface wind speed.

Prediction and Limitations of Noise Maps Developed for Heterogeneous Urban Road Traffic Condition:A Case Study of Surat City,India

Road traffic noise pollution has been recognized as a serious issue which affects human health as well as affects urban regions.Noise maps are very beneficial to identify the impact of noise pollution.A noise mapping study performed to study the propagation of noise in tier-II city along with field measurements.The noise maps are developed using a computer simulation model(SoundPLAN essential 4.0 software).The noise prediction models like U.K’s CoRTN,Germany’s RLS-90,and their modified versions,which can be used for homogenous road traffic conditions,cannot be successfully applied in heterogeneous road traffic conditions of India.In developing country like India,road traffic noise pollution depends on the composition of heterogeneous traffic volume,variance in road geometrical,honking conditions,un-authorized parking,and varying density of the building on either side of the road.These traffic compositions contain vehicles,which have different sizes,speeds variations,a different dimension of vehicles.Because of fluctuating speeds,lack of lane disciplines,and un-authorized parking on main road lanes,honking events becomes inevitable,which changes and affects the urban soundscape of nations like India.Analysis of noise maps showed that horn honking due to un-authorized parked vehicles contributed an additional increase up to 11 dB(A)noise,which is quite significant.

Noise level estimation method with application to EMD-based signal denoising

This paper proposes a new signal noise level estimation approach by local regions. The estimated noise variance is applied as the threshold for an improved empirical mode decomposition（EMD） based signal denoising method. The proposed estimation method can effectively extract the candidate regions for the noise level estimation by measuring the correlation coefficient between noisy signal and a Gaussian filtered signal. For the improved EMD based method, the situation of decomposed intrinsic mode function（IMFs） which contains noise and signal simultaneously are taken into account. Experimental results from two simulated signals and an X-ray pulsar signal demonstrate that the proposed method can achieve better performance than the conventional EMD and wavelet transform（WT） based denoising methods.

Extracting Acoustic Source Information of Shipping Noise for Dynamic Ambient Noise Modelling

Shipping traffic is one of the largest contributors to anthropogenic noise in the ocean. Noise generated by merchant ships elevates natural occurring ambient noise level by 20-30 dB in many areas of the world＇s ocean. In order to model the contributions of the noise generated by merchant ships to underwater ambient noise level correctly, a database that consists of the source levels as a function of frequency for different types of ships is essential. This paper describes the conceptual design, with an emphasis on the characteristics of shipping noise as sound sources, of a marine noise database. It was developed for providing necessary parameters for underwater ambient noise modelling. The parameters relevant to shipping noise modelling are organized in two catalogues： （l） source-receiver geometry related parameters, namely the coordinates of the ships at a given time period, as well as the sizes/types of the ships from which the noise source depths may be derived, and （2） acoustically relevant parameters, i.e., the acoustic SLs （source levels） at given frequencies. An example is presented here to demonstrate the efficacy of this database. The study area is a 117 × 55 km2 region off the coast of La Spezia, Italy, in the Mediterranean Sea.

Assessment of Traffic Noise Pollution in Burla Town,India;An InclusiveAnnoyance Study

Noise pollution is one of the major public health problems in urban areas throughout the world.Noise is unwanted sound which produces undesirable problems in day to day life of human being(e.g.,physiological and psychological problems).Rapid increase of the industrialization,urbanization,infrastructure,volume of motor vehicles,and increase in the road networks brought noise pollution to the highest level of disaster in a current situation.In urban areas,road traffic noise plays commanding role among all noise sources and affects the exposed inhabitants.The present work is done to evaluate and assess the traffic noise and its effects in Burla town.Burla,Vidyanagari of Odisha,is an emerging town in India,as it hosts national level of teaching and research institutions like IIM Sambalpur,a medical college-cum-hospital(VIMSAR),a technical university(VSSUT)and Sambalpur University.In last two decade,the road traffic volume has been increased and is facing severe noise pollution to its inhabitants.Noise pollution assessment was made at different locations of the town.This study unveiled the dismal state of noise pollution in the town.Noise contour maps were drawn to visualize the noise level at the traffic and its surroundings.The numbers of hearing impaired patients in different hospitals of the locality are increasing.That shows grim picture of the situation.Regression equations were established taking noise levels with percentage of highly annoyed people during study indicates strong correlation.

Using Ambient Noise to Study the Seismic Velocity Changes Caused by the Rise and Fall of the Water Level in the Zipingpu Reservoir Region

We study the feature of media changes beneath the Zipingpu reservoir and discuss the process of permeation with the water level rise and fall of the reservoir from January 2005 to January 2008 from ambient noise cross correlation by using continuous seismic data recorded by the stations of Zipingpu seismic network and YZP station. A moving-window cross-spectrum technique has been used to calculate the relative seismic velocity changes between station pairs. Results revealed an obvious relationship between relative seismic velocity, and the water level changes with a time delay that may be caused by permeation during three main impoundments and two large scale disemboguements. Impoundment generates a fast and large impact on the superficial layer, and the changes of seismic velocity is the result of increased pressure and permeation during the impoundment. At the first impoundment, the main effect factor is pressure. During the next two process of impoundment, permeation becomes the main effect factor, affecting the fault at a depth of about 8kin.

Research on Large Volume Airgun Source Signal Reception in Hutubi, Xinjiang Using Seismic Network Data

We used data from the Xinjiang Digital Seismic Network and PSD( Power Spectral Density) method to perform noise level assessment for six stations. We calculated the median of the power spectral density to evaluate the noise level of different stations. After the comparison of the power spectral density of different stations and the airgun signal recognition,we found that noise level of stations with recognizable airgun source signals is lower than that of stations without recognizable signals. The largest difference of the power spectral density is 40 d B,and the smallest is 15 d B. Finally,we found that the failure to recognize the signal of airgun sources at some stations is due to the noise level.

Gender Differences in Auditory Perception and Computational Divided Attention Tasks

Women have been stereotyped as better multitaskers when compared to their male counterparts. The purpose of this study is to investigate whether there are differences in gender performance when performing cognitive combined tasks. Twenty-four graduate students （twelve females and twelve males） volunteered to participate in the study. The task requires participants to indicate when they perceive a change in the intensity of an auditory signal while simultaneously solving algebraic problems. Multivariate Analysis of Variance （MANOVA） results reveal no significant differences between genders when performing the combined tasks （p = 0.1831 and 2 = 0.7891） although the average number of false alarms made during the combined tasks by males is nearly 11% higher than the average number of false alarms made by females. However, （Multivariate Analysis of Variance） ANOVA results for the combined tasks show that males outperform females on the computational task while listening for changes in the auditory signal F（1, 22） - 5.09, p 〈 0.03, but there are no significant differences in their ability to detect noise intensity variation or in the number of false alarms made while multitasking. For the single task analysis the ANOVAs indicate no significant differences in signal detection task performance, computational task performance, or the number of false alarms made by males and females.

Quality analysis of crustal tilt and strain observations in China's earthquakes in 2014

This work analyzes the quality of crustal tilt and strain observations during 2014, which were acquired from 269 sets of ground tiltmeters and 212 sets of strainmeters. In terms of data quality, the water tube tiltmeters presented the highest rate of excellent quality,approximately 91%, and the pendulum tiltmeters and ground strainmeters yielded rates of81% and 78%, respectively. This means that a total of 380 sets of instruments produced high-quality observational data suitable for scientific investigations and analyses.

Field acoustic measurements of high-speed train sound along BTIR

In this paper,single-point field measurements of noise radiated from high-speed trains were performed at two sites along Beijing-Tianjin intercity railway(BTIR),aiming at acquiring the realistic acoustic data for validation and verification of physical model and computational prediction.The measurements showed that A-weighted sound pressure levels(SPLs) were between 80 and 87 dBA as trains passed.The maximum noise occurred at the moment when the pantograph arrived,suggesting that pantograph noise was one of the most significant sources.Sound radiated from high-speed trains of BTIR was a typical broadband spectrum with most acoustic power restricted in the range of medium-high frequency from about 400 Hz to 5 kHz.Aerodynamic noise was shown to be the dominant one over other acoustic sources for high-speed trains.

Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient vibration tests in Shiraz-Iran

The main purpose of the present study is to enhance high-level noisy data by a wavelet-based iterative filtering algorithm for identification of natural frequencies during ambient wind vibrational tests on a petrochemical process tower.Most of denoising methods fail to filter such noise properly.Both the signal-to-noise ratio and the peak signal-to-noise ratio are small.Multiresolution-based one-step and variational-based filtering methods fail to denoise properly with thresholds obtained by theoretical or empirical method.Duc to the fact that it is impossible to completely denoise such high-level noisy data,the enhancing approach is used to improve the data quality,which is the main novelty from the application point of view here.For this iterative method,a simple computational approach is proposed to estimate the dynamic threshold values.Hence,different thresholds can be obtained for different recorded signals in one ambient test.This is in contrast to commonly used approaches recommending one global threshold estimated mainly by an empirical method.After the enhancements,modal frequencies are directly detected by the cross wavelet transform(XWT),the spectral power density and autocorrelation of wavelet coefficients.Estimated frequencies are then compared with those of an undamaged-model,simulated by the finite element method.

Indoor environmental quality(IEQ)assessment of Nigerian university libraries:A pilot study

An indoor environmental quality(IEQ)assessment of academic libraries in Nigeria was conducted through ob-jective measurements.The selected university libraries were Abubakar Gimba Library;Awwal Ibrahim Library;and Ibrahim Badamosi Babangida Library Complex.The libraries were evaluated under operating conditions and during their peak usage periods.Measurements of the main descriptors of good IEQ,including the acoustical,visual,and thermal comfort conditions were performed using portable IEQ meters.The methodology employed for the assessment of these IEQ descriptors followed prescriptions of international standards ASHRAE standard 55 and ISO 7730.To determine the time of the day in which the library buildings can achieve optimum IEQ,measurements were taken in the morning and afternoon.The results obtained were compared with reference values found in the international Standard CIBSE Guide A for adequate IEQ compliance of academic libraries.The findings of this study are expected to help in improving the IEQ of academic libraries in Nigeria and other parts of the world.