Acoustic Absorber In article number 2201757, Gih-Keong Lau and co-workers report that a single type of absorber does not completely mitigate the variable noise whose frequency shifts with vehicle speed load. A transformable switches from Helmholtz resonance at medium to membrane low is developed. Electro-adhesive zip double micro-slit layers helps reduce effective hole ratio. This transparent c...

A numerical investigation was carried out in order to predict the effects of symmetric heating on irregular acoustic streaming in air-filled shallow enclosures. The fluid motion is driven by periodic vibration of the enclosure left wall. The vertical walls of the enclosure are adiabatic while the horizontal walls are heated symmetrically. A control-volume method based, explicit time-marching Fl...

This paper presents a multichannel active system for the local control of sound around the headrest on the back of a seat placed inside an enclosure. The size of the zones of quiet produced makes the system practical only at relatively low frequencies [1]. Finally, some results of cancellation for narrowband and broadband noise are presented. Two different system configurations algorithms have ...

A convenient mathematical formulation is given for the absolute lowfrequency response of an electrodynamic direct radiator loudspeaker mounted in a vented or unvented enclosure. The combined effects of speaker Q (ratio of reactance to resistance), enclosure size, and enclosure tuning are shown to control the convergence of the response curve towards ts asymptotic value. Mathematical criteria ar...

In this paper, a numerical model of rectangular enclosure with apertures and a real receiving dipole antenna is considered for the purpose of accurate electric shielding effectiveness calculation. Dipole antenna is often used in practice to measure the level of electromagnetic field at some points inside the enclosure in order to estimate its shielding efficiency. Transmission-line matrix (TLM)...

Enclosure and Acacia shade availability to plants are basic variable in arid and semi-arid rangelands. the aim of this study was investigation the impact of patch enclosure and Acacia shade using four treatments which are Inside Enclosure Under Acacia shade (IEUA), Inside Enclosure Without Acacia shade (IEWA), Outside Enclosure Under Acacia shade (OEUA) and Outside Enclosure W...

X-ray imaging instruments will operate in a harsh ionizing radiation background environment on implosion experiments at the National Ignition Facility. These backgrounds consist of mostly neutrons and gamma rays produced by inelastic scattering of neutrons. Imaging systems based on x-ray framing cameras with film and CCD’s have been designed to operate in such harsh neutron-induced background e...

Competitive audio consumer products require not only cheap signal processing hardware but also low-cost analog equipment and sound transducers. The nonlinear distortions produced by these electro-acoustic transmission systems cannot be described and analyzed by standard methods based on linear systems theory alone. In order to take the nonlinear properties into account, we present a measurement...

Abstract The hull is an important component of the submarine structure, and it also one factors that affect concealment submarine. By using finite element method, a model was established to analyze hydrodynamic noise at contact points between front rear under different diving angles. results show when angle about 10°, positions enclosure relatively small. research provide reference for ensuring...

EM1 from slots and apertures resulting from coupling of interior sources through enclosure cavity modes in a Sun S-1000 workstation was investigated. The excitation of a specially designed rectangular enclosure with a slot was also studied experimentally and with finite-difference time-domain (FDTD) simulations. The radiated power results for both the S-1000 and simple rectangular enclosure ind...