This paper describes the development of a Retrievable Subsurface Accelerometer (RSA) for the NSF George E. Brown, Jr., Network for Earthquake Engineering Simulation (NEES) project at UCLA. The RSA was developed to obtain subsurface vibration data during forced-vibration experiments and aftershock events. The RSA can be rapidly installed using a CPT truck and subsequently retrieved using structu...

Aiming to improve survey accuracy of Measurement While Drilling (MWD) based on Fiber Optic Gyroscopes (FOGs) in the long period, the external aiding sources are fused into the inertial navigation by the Kalman filter (KF) method. The KF method needs to model the inertial sensors' noise as the system noise model. The system noise is modeled as white Gaussian noise conventionally. However, becaus...

Fiber-optic gyroscopes (FOGs)-based Measurement While Drilling system (MWD) is a newly developed instrument to survey the borehole trajectory continuously and in real time. However, because of strong vibration while drilling, measurement accuracy FOG-based MWD deteriorates. It urgent improve drilling. Therefore, this paper proposes an innovative scheme for error MWD. Firstly, nonlinear models F...

The interaction between friction and vibration is a widely recognised source of inefciency in all mechanical systems. The nature of this interaction is very dependent on the dynamic environment and its control requires a detailed understanding of the mathematical structure governing the stability of this environment. Although the fundamental causes of friction-induced intermittent motion have b...

BACKGROUND The purpose of our study was to investigate the impact of distracting noise on the performance on a simulated orthopedic bone drilling skill when that noise blocks routine auditory feedback associated with the sounds of the drill. METHODS Medical students (n=11), intermediate residents (postgraduate years 3-5, n=10) and surgeons (n=8) each drilled 20 bicortical holes in a femur bon...

Vibration is commonly used in civil engineering applications to efficiently compact aggregates. This study examined the effect of vibration and drainage on bone graft compaction and cement penetration in an in vitro femoral impaction bone grafting model with the use of 3-dimensional micro-computed tomographic imaging. Three regions were analyzed. In the middle and proximal femoral regions, ther...