Sound reflection measurements on noise barriers in critical conditions

Garai, Massimo; Guidorzi, Paolo

doi:10.1016/j.buildenv.2015.06.023

Cited by 23 publications

(10 citation statements)

References 8 publications

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“…These disseminate as plane waves in the tube, hit the sample and are reflected resulting in a standing wave interference pattern. The third method is reflection method, giving results valid for direct (normal or oblique) incidence in a non-diffuse sound field [3].…”

Section: Introductionmentioning

confidence: 99%

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Influence of Density on Sound Absorption Coefficient of Fibre Board

Nandanwar¹,

Kiran²,

Varadarajulu³

2017

OJA

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For acoustic applications such as theaters, cinema halls, auditoriums the data on acoustic properties i.e. sound absorption coefficient and sound transmission loss are required to evaluate the acoustic behavior of panel products and to facilitate the necessary design computations. Fibre boards are widely used in private and commercial buildings, but not much data are available on acoustic efficiency of fibre boards. The study was carried using acoustic pulse tester based on standing wave method for evaluating sound absorption coefficient. Wood fibre boards of different densities ranging from 200 to 800 kg/m 3 were taken and their sound absorption coefficients at frequencies ranging from 125 Hz to 4000 Hz were evaluated in third octave band. Noise reduction coefficient of the samples was also computed. From the study, it is observed that low density fibre board possess high sound absorption coefficient and noise reduction coefficient when compared with high density fibre boards. It was seen that sound absorption coefficient increases with decrease in density and vice versa.

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Section: Introductionmentioning

confidence: 99%

“…Garai [3] presented a series of experiments designed to put in evidence the differences between Reflection Index measurements performed in the mentioned critical conditions, according to the QUIESST guidelines, done using MLS (Maximum Length Sequence) or ESS (Exponential Swept-Sine) signals.…”

Section: Introductionmentioning

confidence: 99%

Influence of Density on Sound Absorption Coefficient of Fibre Board

Nandanwar¹,

Kiran²,

Varadarajulu³

2017

OJA

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“…Knowing the speed of sound, corrected according to the average air temperature for more accuracy, the 4 distances from the microphone to the 4 known points (loudspeakers) are obtained and with the algorithm described above, the position in the 3D space of the microphone and thermocouple is found (Guidorzi 2017). The idea of the position detection system was born from the need to correctly position microphones during measurements on road noise barriers (Garai and Guidorzi 2015). The temperature from the thermocouple is detected by an Arduino system, as shown in Figure 3b, interfaced directly with the software for measuring the position on the computer, illustrated in Figure 5a.…”

Section: Experimental Measurements and The Model Validationmentioning

confidence: 99%

Evaluation of Thermal Comfort Inside an Office Equipped with a Fan Coil HVAC System: A CFD Approach

Semprini

Jahanbin

Pulvirenti

et al. 2019

Future Cities and Environment

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Introduction Most industrialized countries, in particular the European Union countries, are in shifting phase from a fossilbased development to a sustainable development. Approximately 40% of the energy consumption in the European Union is attributed to buildings across the private and public sectors. The European Parliament Directive 2010/31 (The Directive 2010/31/EU) states that new buildings should consume very low amount of fossil-based energy (Nearly Zero Energy Buildings) by 2020. The Directive declares that all new buildings built after 31 December 2018 will have to be buildings with high energy performance and their required amount of energy should be mostly covered by renewable energy sources. Hence, energy efficiency has become a common target for all buildings, in particular historical buildings (Fotopoulou et al. 2018). Since buildings with historic value are less energy-efficient than modern ones, energy demand and indoor comfort expectations are critical challenges for them.

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“…Due to the effect of time aliasing, the initial part of the impulse response that precedes the arrival of the transmitted sound is governed by the tail of the impulse response [14]. Note that this effect is not apparent when using an ESS signal [8]. Therefore, the "noise" segment used for signal-to-noise ratio calculations in this work is based on a segment of the impulse response tail ( Figure 2).…”

Section: Signal-to-noise Ratiomentioning

confidence: 99%

“…Measurements can be conducted in the presence of background noise due to the use of impulse response measurement techniques using deterministic excitation signals. It should noted that these test signals can include MLS (Maximum Length Sequence) and ESS (Exponential Sine Sweep), which may give slightly different results in critical conditions [8]. For this study the MLS test signal has been employed.…”

Section: Introductionmentioning

confidence: 99%