نتایج جستجو برای: shock waves

تعداد نتایج: 211177  

Journal: :Gut 1990
A Darzi I Reid E Kay J R Monson W A Tanner F B Keane

Controversy surrounds the capacity of extracorporeal shock wave lithotripsy to cause soft tissue injury. This study examines the influence of different dosages of shock waves on the gall bladder in both humans and an animal model. Sixty one guinea pigs were divided into groups and subjected to different numbers of shock waves (6,000, 24,000, and 48,000) at different frequencies (2.5, 5.0, 10, 2...

2002
Scott McClure

What are shock waves? Extracorporeal shock waves are pressure waves generated outside the body that can be focused at a specific site within the body. Shock waves are characterized by high positive pressures, up to 100 MPa (over 100 times atmospheric pressure), and negative pressures of 5-10 MPa. They have a rapid rise time of 30-120 nanoseconds (10-9) and a short, 5 microsecond (10-6) pulse du...

2010
Michael W. Courtney

The prevalence of blast induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more conv...

2002
Stephen Schecter S Schecter

For a system of conservation laws in one space dimension, we identify all structurally stable Riemann solutions that include only shock waves. Shock waves are required to satisfy the viscous profile criterion for a given viscosity (B(u)ux)x . Undercompressive shock waves are allowed. We also show that all such Riemann solutions have nearby smooth solutions of the Dafermos regularization with th...

2006
Yuri Lyubarsky

It is argued and demonstrated by particle-in-cell simulations that the synchrotron maser instability could develop at the front of a relativistic, magnetized shock. The instability generates strong low-frequency electromagnetic waves propagating both upstream and downstream of the shock. Upstream of the shock, these waves make electrons lag behind ions so that a longitudinal electric field aris...

2010
L. B. Wilson C. A. Cattell P. J. Kellogg K. Goetz K. Kersten J. C. Kasper A. Szabo M. Wilber

[1] We present the first observations at an interplanetary shock of large‐amplitude (> 100 mV/m pk‐pk) solitary waves and large‐amplitude (∼30 mV/m pk‐pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein‐like waves show enhanced power at integer and half‐integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, co...

2017
Nejc Lukac Blaz Tasic Muc Matija Jezersek Matjaz Lukac

A new SWEEPS (Shock Wave Enhanced Emission Photoacoustic Streaming) modality for Er:YAG laser is presented, developed especially to improve the cleaning and disinfecting efficacy of laser-assisted endodontic procedures. Typically, shock waves are not emitted during laser-assisted irrigation of spatially confined root canals. However, by using the new SWEEPS modality, an acceleration of the coll...

In this paper, an efficient numerical scheme based on uniform Haar wavelets is used to solve the non-planar Burgers equation. The quasilinearization technique is used to conveniently handle the nonlinear terms in the non-planar Burgers equation. The basic idea of Haar wavelet collocation method is to convert the partial differential equation into a system of algebraic equations that involves a ...

2013
Kristin Kirkby

Shock waves, high-energy sound or pressure waves (like thunder following lightening or a small, focused explosion), have little to do with electric shock. Shock waves can be generated in many ways, but electrohydraulic devices have the greatest capacity to produce and project high energy to a deep focal depth. ESWT can be highly focused and can achieve a focal point beyond 10 cm into deeper tis...

Journal: :SIAM Journal of Applied Mathematics 2008
James Glimm Xiaomei Ji Jiequan Li Xiaolin Li Peng Zhang Tong Zhang Yuxi Zheng

It is perhaps surprising for a shock wave to exist in the solution of a rarefaction Riemann problem for the compressible Euler equations in two space dimensions. We present numerical evidence and generalized characteristic analysis to establish the existence of a shock wave in such a 2D Riemann problem, defined by the interaction of four rarefaction waves. We consider both the customary configu...

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