Mohammed Abd-Elbasseer

National Institute of Standards (Egypt) | NIS · Acoustics Department

English language as a non-native language is the most common language over the world, it is the language of conferences, business and the airports. While the Arabic language is the native language of Egypt, the English language is considered as the second language. This research will conduct to investigate the effect of speech level, rate and repet...

It is an important to clarify standard uncertainity of material size (area of sample) effect on its sound absorption coefficient in reverberatin room. Measurements were carried out for foam, sponge, rubber and carpet materials, to determine the effect of area on sound absorption coefficient. The tested surface areas ranged from 4m2 to 14m2, the abs...

There are several methods to decrease acoustic noise. Sound absorption is one of the noise control methods, commonly, multi-layer sound absorbers are applied to absorb broad band noise. , the sound absorption coefficient of different materials are measured in impedance tube using two-microphone transfer-function method according to ISO 10534-2 and...

Micro-perforated panel sound absorber is becoming increasingly popular in buildings as an unconventional sound absorber compared with prominent porous materials. To increase the bandwidth, a single micro-perforated panel with another single micro-perforated panel can be cascaded to form a double micro-perforated panel. This paper looks at the influ...

Micro-perforated panels have become a valid broadband sound absorber option lately. Their applicability is wide since they are promising for absorbing sound energy for several applications, such as automotive, HVAC systems, noise barriers, etc. This study investigates the effect of different distribution patterns of holes, perforation ratio, air ga...

The purpose of this article is study the effect of room variable conditions (volume, reverberation time and the averaging of sound level) on the uncertainty values of sound power level (L w) using a reference sound source (RSS) in situe, for sound power level determination. The measurements have been carried out in a reverberation room of volume 15...

The essential target of this investigation is to valorize an Eichhornia crassipes fiber (ECF) and maleates of Eichhornia crassipes fiber (MoECF) as reinforcing fillers in styrene‐butadiene rubber (SBR) composites in terms of the mechanical, acoustical, thermal, and morphological properties. Fourier transforms infrared spectroscopy characterizes the...

This research presents a thorough evaluation of the reverberation room at Acoustics Laboratory in National Institute of Standards (NIS) according to the related international standards. The evaluation aims at examining the room performance and exploring its effectiveness in the frequency range from 125 Hz to 10000 Hz according to the international...

Statistical Energy Analysis (SEA) is statistical in that frequencies of resonance for each subsystem are assumed to be uniformly distributed in frequency within each of the frequency bands used in the analysis since it is assumed that energy resides only in resonance modes, the total energy in each subsystem is the sum of the energies in the modes....

Using of suitable acoustic material panels between the source and the effected people to reduce the transmitted noise is necesSary. The sound transmission coefficient of the panel is the fraction of sound power in the incident air-borne wave that appears in the transmitted air-borne wave on the secondary of the panel. The sound transmission loss of...

The study of the passive control technique of noise through a perforated panel with resonators is useful in acoustic barrier design for both industrial and traffic noise. The loss mechanisms that reduce the energy of sound have been considered in the method for predicting the TL of compound flat panels containing Helmholtz resonators. A transmissio...