منابع مشابه
Attenuation of noise by motorcycle safety helmets.
For workers such as police motorcyclists or couriers, traffic and engine noise reaching the ears is an important factor contributing to the overall condition of their work. This noise can be reduced with motorcycle helmets. In this study, insertion loss of motorcycle helmets was measured with the microphone-in-real-ear technique and sound attenuation with the real-ear-at-threshold method. Resul...
متن کاملEvaluation of effect of gold nanorods and spherical gold nanoparticles of different sizes on X-ray attenuation in computed tomography
Introduction: To date, gold nanoparticles (GNPs) have been demonstrated to have great potential as contrast agent for CT imaging and therapeutics. This study was designed to evaluate any effect on X-ray attenuation that might result from using GNPs with a variety of size, surface chemistries and shapes. Materials and Methods: Spherical GNPs and gold nanorod...
متن کاملSafety helmets
helmet of the water flea (Daphnia spp.) does not make it invisible, but it does confer some protection against predators by making the fleas harder to catch. Water fleas do not necessarily begin life with a helmet but can form one as a morphological defence in response to chemicals released by their predators. The images above show three pairs of water fleas from different species; the non-helm...
متن کاملSurgical Helmets and SARS Infection
Performance testing of two brands of surgical helmets indicated that their efficiency at in vivo filtration of sub-micrometer-sized particles is inadequate for their use as respirators. These helmets are not marketed for respiratory protection and should not be used alone for protection against severe acute respiratory syndrome when performing aerosol-generating procedures.
متن کاملProtective capability of bicycle helmets.
Cycle helmets that meet UK and US standards have been tested. The mechanisms of energy absorption for frontal and side impacts have been analysed. A good helmet should protect the wearer for impacts up to 15 mph into a rigid flat surface.
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ژورنال
عنوان ژورنال: The Journal of the Acoustical Society of America
سال: 1959
ISSN: 0001-4966
DOI: 10.1121/1.1930205