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

Journal of Forestry Research 2016年第2期27卷 463-468页

作者： Seyed Ata Ollah Hosseini Seyran Zandi Asghar Fallah Mehran Nasiri Department of Forestry and Forest Economics Faculty of Natural Resources University of Tehran Department of Forestry Faculty of Natural Resources Sari University of Agricultural Sciences and Natural Resources Alborz Road Development and Construction Corporation Civil Engineers office

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.

关键词： Forest road noise pollution noise level Vegetation Distribution

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Field acoustic measurements of high-speed train sound along BTIR

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Science China(Physics,Mechanics & Astronomy) 2013年第2期56卷 474-482页

作者： YU HuaHua LI JiaChun Institute of Mechanics Chinese Academy of Sciences

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 *** measurements showed that A-weighted sound pressure levels(SPLs) were between 80 and 87 dBA as trains *** maximum noise occurred at the moment when the pantograph arrived,suggesting that pantograph noise was one of the most significant *** 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 *** noise was shown to be the dominant one over other acoustic sources for high-speed trains.

关键词： field measurement noise level Beijing-Tianjin intercity railway high-speed trains

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

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Energy and Built Environment 2021年第3期2卷 302-314页

作者： Williams P Akanmu Sunday S Nunayon Uche C Eboson Department of Building School of Environmental TechnologyFederal University of TechnologyMinnaP.M.B 65MinnaNiger StateNigeria Department of Architecture and Civil Engineering City University of Hong KongTat Chee AvenueKowloonHong Kong

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

关键词： Comfort conditions Illuminance Indoor environmental quality Nigerian university libraries noise level Thermal comfort

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

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Sound & Vibration 2021年第1期55卷 57-68页

作者： Dipeshkumar R.Sonaviya Bhaven N.Tandel Civil Engineering Department SVNITSuratIndia

Road traffic noise pollution has been recognized as a serious issue which affects human health as well as affects urban *** 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 *** 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 *** 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 *** traffic compositions contain vehicles,which have different sizes,speeds variations,a different dimension of *** 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 *** 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.

关键词： noise level noisemapping predictionmodels roadtraffic noise

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Comparison of noise-levels between superconducting gravimeter and gPhone gravimeter

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Geodesy and Geodynamics 2018年第6期9卷 498-503页

作者： Kun Zhang Ziwei Liu Xiaotong Zhang Ying Jiang Institute of Seismology China Earthquake Administration Wuhan 430071 China Key Laboratory of Earthquake Geodesy China Earthquake Administration Wuhan 430071 China

关键词： Superconducting gravimeter gPhone gravimeter noise level SNM SSNM

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

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Earthquake Research in China 2016年第3期30卷 326-332页

作者： Su Jinbo Wang Qiong Wang Haitao Shi Yongjun Chen Xiangjun Feng Lei Chen Hao Zhang Wenxiu Earthquake Administration of Xinjiang Uygur Autonomous Region Urumqi 830011 China Lanzhou Institute of Seismology CEA Lanzhou 730000 China

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.

关键词： Large volume airgun Power Spectral Density noise level Signal recognition

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CMOS RF Receiver:From System Architecture to Circuit Implementation

CMOS RF Receiver:From System Architecture to Circuit Impleme...

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2005 6th International Conference on ASIC

作者： Pengfei Zhang Beken Corporation

1 Introduction Traditionally,RF receivers were constructed with discrete *** microwave monolithic integrated circuits(MMIC) were predominately fabricated inⅢ-Ⅴcompounds(GaAs),taking advantage of the high carrier mobility,the high substrate resistance(which made high quality passive components possible) and the high break-down voltage.A larger scale of integration was achieved at the advent of silicon bipolar junction transistor(BJT) technology,especially when SiGe HBT became available where the transistor cut-off frequency(f) can be at tens of ***,on the other hand,has long been considered slow and noisy,therefore not suitable for RF applications. However,the aggressive scaling of the feature size,even thought solely driven by digital applications,resulted in a strong improvement in the RF performance of the CMOS *** early 90’s,increasingly more investment and

关键词： Radio frequency Circuits Receivers noise figure Background noise Wireless communication noise level Signal to noise ratio Costs Bandwidth

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