acoustics instrument Articles

  • Rapid detection of sewer defects and blockages using acoustic-based instrumentation

    Sewer flooding incidents in the UK are being increasingly associated with the presence of blockages. Blockages are difficult to deal with as although there are locations where they are more likely to occur, they do occur intermittently. In order to manage sewer blockage pro-actively sewer managers need to be able to identify the location of blockages promptly. Traditional closed-circuit ...


    By IWA Publishing

  • On the right track

    High-speed train manufacturer, CAF, rely on world-class beamforming technology to reduce the noise generated by their trains – helping to make high-speed trains a more viable option for travellers and operators alike. Because of its relatively low levels of CO2 emissions, train travel is considered one of the ...

  • Fine-tuning acoustic isolation in buildings

    ACCIONA Infrastructure is ranked among the leading construction companies in the world - and is recognised for implementing the most advanced and innovative technology.  As research and design is vital to keep the company at the cutting edge in relation to technological developments, ACCIONA Infrastructure created a team to analyse noise and vibration. Where traditional ...

  • Measuring the Dispersion Coefficient with Acoustic Doppler Current Profilers

    Abstract: A method is evaluated for estimating the longitudinal dispersion coefficient K from velocities and bathymetry measured with an acoustic Doppler current profiler #1;ADCP. If shear dispersion controls the mixing, the dispersion coefficient can be estimated from measurements of velocity and depth in a cross section. The dispersion coefficient has typically been measured by costly and ...


    By Teledyne RD Instruments

  • A novel acoustic imaging tool for monitoring the state of rapid sand filters

    A new technology based on acoustic waves is developed to monitor the state of sand filters used in drinking water treatment. Changes in the sand filter, due to the removal of suspended particles from the water and their accumulation in the pores, result in an increase of the bulk density and acoustic speed of the granular material. Consequently, the reflected acoustic response changes as the ...


    By IWA Publishing

  • Coupling acoustic devices for monitoring combined sewer network sediment deposits

    Combined sewer networks display some unique features that are not easily reproducible in the laboratory and have yet to be well understood. The transport of organic and mobile sediments, present in large quantities despite the use of optimal design practices, dramatically changes sewer flow patterns and the interaction between flow and sediment. To understand both the flow patterns and transport ...


    By IWA Publishing

  • Suspended particles in wastewater: their optical, sedimentation and acoustical characterization and modeling

    Wastewater regulation and treatment is still a major concern in planetary pollution management. Some pollutants, referred to as particulate matter, consist of very small particles just suspended in the water. Various techniques are used for the suspended particles survey. Few of them are able to provide real-time data. The development of new, real time instruments needs the confrontation with ...


    By IWA Publishing

  • Estimating longitudinal dispersion in rivers using Acoustic Doppler Current Profilers

    Abstract The longitudinal dispersion coefficient (D) is an important parameter needed to describe the transport of solutes in rivers and streams. The dispersion coefficient is generally estimated from tracer studies but the method can be expensive and time consuming, especially for large rivers. A number of empirical relations are available to estimate the dispersion coefficient; however, ...


    By Teledyne RD Instruments

  • Manage the rise in deafness claims with Pulsar Instruments

    The recent reports in the press about insurance groups complaining of a sharp rise in claims from employees seeking compensation for hearing problems have highlighted the real risks of noise induced hearing loss and the importance of protecting employees in the workplace. Although employees are protected by Law, noise induced hearing loss is often ignored. And once hearing loss has occurred, it ...


    By Pulsar Instruments plc

  • Attenuation of an ultrasonic beam by suspended particles and range of acoustic flow meters in sewer networks

    Ultrasonic flow meters are commonly used in wastewater management. Under certain circumstances, a reduction in the flow meter range may occur and cause significant error in the flow rate measurement. Attenuation due to suspended particles is one of the phenomena capable of reducing the flow meter range. The present paper examines attenuation resulting from re-suspended pond sediment over a wide ...


    By IWA Publishing

  • Sooty tern conservation - Scarecrow bio-acoustic systems play a part in sooty tern conservation

    Scarecrow Bio-Acoustic Systems, a leading international innovator in bird dispersal technology has been instrumental in helping the Sooty Tern recolonise one of its former nesting sites, bringing the seabird back to Denis Island in the Seychelles, after an absence of over one hundred years. Until recently, Uckfield based Scarecrow Bio-Acoustic Systems Ltd has been renowned for developing leading ...

  • Statistical quality control of streamflow measurements with moving-boat acoustic Doppler current profilers

    This technical note presents a new methodology for the statistical quality control of streamflow measurements with moving-boat acoustic Doppler current profilers. The methodology consists of two alternative acceptance criteria: uncertainty-based and residual-based. The former uses the uncertainty and the latter uses the maximum residual as a measurement quality indicator. Application examples are ...


    By Teledyne RD Instruments

  • Uncertainties in Environmental Noise Assessments - ISO 1996 - Effects of Instrument Class and Residual Sound

    ISO/DIS 1996-2.2 (2005) “Acoustics — Description, assessment and measurement of environmental noise — Determination of environmental noise levels” contains guidelines on assessing the uncertainties of the determined sound pressure levels. This depends on the sound source, measurement time interval, weather conditions, distance from the source, measurement method and instrumentation. Guidelines on ...

  • Diurnal variation of the mixing-layer height and polonium concentration in the air

    The Mixing Height (MH) is one of the most important parameters that characterise the range of the atmospheric turbulence. This parameter shows characteristic diurnal variation but cannot be measured immediately. Therefore, it is evaluated indirectly by measuring other quantities. The measurement of radon concentration in the atmospheric air is one of the methods using natural occurring ...


    By Inderscience Publishers

  • INTA – exterior noise certification of Airbus A330 MRTT

    INTA is a Public Research Body specialising in aeronautic and space research and technological development. It owns a multitude of Brüel & Kjær products including a 30-channel PULSE system and a 6-channel LAN-XI system which are used daily. One of the latest and most important jobs performed by INTA is the Noise Certification of Airbus Military’s A330 MRTT which it achieved ...

  • Impact of sound attenuation by suspended sediment on ADCP backscatter calibrations

    Abstract. Although designed for velocity measurements, acoustic Doppler current profilers (ADCPs) are widely being used to monitor suspended particulate matter in rivers and in marine environments. To quantify mass concentrations of suspended matter, ADCP backscatter is generally calibrated with in situ measurements. ADCP backscatter calibrations are often highly site-specific and season ...


    By Teledyne RD Instruments

  • Baseline data in air quality impact studies

    The main objective of this paper is to explain not only the importance of the baseline data in air quality studies but also the general procedures and steps involved in the baseline data collection. Special considerations on the instruments and measurements for a perfect baseline data collection are also emphasized in this paper. As an example, an adequate baseline data collection procedure which ...


    By Inderscience Publishers

  • Sonic temperature significance and limitations

    The ATI sonic thermometer measures temperature from transit times t1 and t2 measured along the vertical path of the anemometer's probe. They are the times taken by sound pulses to traverse the 15-cm acoustic path in opposite directions; (these same transit times are used also for computing the vertical wind component). The instrument exploits the strong dependence that exists between the speed ...

  • How the LISST-ABS works

    INTRODUCTION: Sequoia’s Acoustic Backscatter Sensor, LISST-ABS is designed to measure suspended sediment concentration at a point. Unlike ADCP’s which may record similar backscatter strength at multiple points along the acoustic beams (‘ranges’), the LISST-ABS  only reports backscatter signal strength at a single point about 5 cm from the transducer. The ...


    By Sequoia Scientific, Inc.

  • Noise Monitors and Meters

    Sound level meters Description and ApplicationsThe sound level meter is a lightweight instrument for the measurement of sound pressure level (SPL) in decibels. All ANSI-approved meters meet minimum requirements that include an A-weighted network, a slow-response meter characteristic, and a fully graduated scale with measurements ranging from 80 to 130 dBA. The Type II meter is most frequently ...

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