Infrasound from thunder: A natural seismic source

The rotary subwoofer: a controllable infrasound source.

The rotary subwoofer is a novel acoustic transducer capable of projecting infrasonic signals at high sound pressure levels. The projector produces higher acoustic particle velocities than conventional transducers which translate into higher radiated sound pressure levels. This paper characterizes measured performance of a rotary subwoofer and presents a model to predict sound pressure levels.

Evaluation of infrasound signals from the shuttle Atlantis using a large seismic network.

Inclement weather in Florida forced the space shuttle "Atlantis" to land at Edwards Air Force Base in southern California on June 22, 2007, passing near three infrasound stations and several hundred seismic stations in northern Mexico, southern California, and Nevada. The high signal-to-noise ratio, broad receiver coverage, and Atlantis' positional information allow for the testing of infrasoun...

Gifts from the Thunder Beings

Infrasound events detected with the Southern California Seismic Network

[1] We examine continuous data from the Southern California Seismic Network from 2003 and identify infrasound acoustic waves from 76 previously undetected events. Using waveform cross-correlation of the signal envelope functions, we determine their relative arrival times and estimate source locations. The waves travel at acoustic speeds of 320 m/s and are observed in seismic records up to 450 k...

A Novel Approach for Direct Preparation of Hydroxyapatite Nanoparticles from natural source using Microwave

Hydroxyapatite (HA) is one of the most common biocompatible ceramic with wide usages in various aspects of medicine due to the resemblance to the mineral bone tissue. The particle size of HA has a key roll in determination of the reaction rate at the interface of natural bones/artificial. Accordingly, this paper tries to propose a novel approach for the preparation of HA nanoparticles from natu...