This work focuses on the study of shield systems consisting nested enclosures. In first step, using FDTD simulations and measurements in an anechoic chamber, we investigate shielding effectiveness (SE) system two rectangular enclosures frequency range up to 3 GHz. It is shown for time that a number frequencies, SE shields can be improved by 40–50 dB due asymmetric arrangement enclosures, their ...

Department of Mechanical Engineering, The Hong Kong Polytechnic University Hung Home, Kowloon, Hong Kong, SAR of China Email address: [email protected]. Abstract This paper examines the influence of the internal resistance of a Helmholtz resonator on the noise control in a small enclosure. The absorptive process mainly occurring within the neck of a Helmholtz resonator provides the resonator w...

in the present study, mixed convection laminar flow around an adiabatic body in a lid-driven enclosure filled with nanofluid using variable thermal conductivity and variable viscosity is numerically investigated. the fluid around the body in the enclosure is a water-based nanofluid containing al2o3 nanoparticles. the vertical enclosure’s walls are maintained at constant cold temperature and the...

The portable generators are the main means of compensating the shortage of national electricity power as in Iraq. However, their noise causes a huge disturbance, uncomforting and loss of concentration of the nearby resident. This problem requires a solution because most shops and residential houses use generators. Covering method is a simple and relatively low cost one for reduction of generato...

Three enclosures (10 x 10 x 1.5-1.3 m in depth) were set beside Dianch Lake, Kunming, People's Republic of China, for the period from July 28 to August 26, 2002. The enclosures were filled with cyanobacterial (Microcystis aeruginosa) water bloom-containing lake water. Lake sediment that contained macrophytes and water chestnut seeds was spread over the entire bottom of each enclosure. Initially...