An extensive program of full-scale ambient vibration testing has been conducted to measure the dynamic response of a 240 meter cable-stayed bridge–Gi-Lu Bridge in Nan-Tou County, Taiwan. A MEMS-based wireless sensor system and a traditional microcomputer-based system were used to collect and analyze ambient vibration data. A total of four bridge modal frequencies and associated mode shapes were...

In this work, machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic...

The seismoscope is a simple instrument designed originally to give a largely qualitative indication of the strong ground motions produced by an earthquake. It consists of a smoked watch glass attached to a two-degree-of-freedom pendulum with a period of 1⁄4 sec and damping about 10 per cent of critical; a pen records the pendulum motions on the watch glass. One point on the displacement spectru...

This paper presents a dual-stage control system design method for the rotational maneuver and vibration stabilization of a spacecraft with flexible appendages. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. The design of attitude controller was based on sliding mode control (SMC) theory leading to a discontinuous cont...

INTRODUCTION The introduction of piezoelectric instruments in endodontic surgery allowed clinicians to manage the bone tissue with precision reducing the risk of damaging soft tissues. Although such instruments can also be used to prepare root-end cavity, few information is available on the effect of piezosurgery on dentine. This cadaveric study investigated the integrity of root apices after r...

A hybrid control scheme for vibration reduction of flexible spacecraft during rotational maneuvers is investigated by using variable structure output feedback control (VSOFC) for attitude control and smart materials for active vibration suppression. The proposed control design process is twofold: design of the attitude controller using VSOFC theory acting on the hub and design of an independent...

Vibration analysis can be used as a more sensitive alternative to conventional techniques for the detection of loosening of total hip replacement (THR) components. The vibration modes of the human femur and of selected THR prosthetic stems were studied by experimental modal analysis using a CADA-X system and by finite element simulation using MARC/Mentat software. Two hypotheses were formulated...

Due to the lower tool as the research object to analyze the vibration of the drill string, causes the loss of the low order natural frequency of the drill string and the inherent vibration mode, give rise to the distortion and error of the result from the transient analysis of the drill string. For this purpose, the whole drill string of the deep wells is studied in the article, build the mecha...

This paper describes a method for correcting the dynamically induced bias errors in wind tunnel model att i tude measurements using measured modal properties of the model system. At NASA Langley Research Center, the predominant instrumentation used to measure model attitude is a servo-accelerometer device that senses the model attitude with respect to the local vertical. Under smooth wind tunne...

With the increase of social demand on environmental quality, the clean coal technology (CCT) is one of the most effective measures for environmental control. It is an important means in CCT to decrease the gangue content. Targeting at distinguishing the top-coal and gangue, this paper discussed coalgangue interface detection on fully mechanised mining face. The Hilbert marginal spectrum based o...