whole body vibration can deteriorate health bringing about or back pain or spinal column injury, resulted from continuing exposure to vibration. also exposure to vibration can cause disorder in central nervous system and adversely influence vascular and skeletal systems. in this research, the vibration of universal 650m tractor seat and its effect on the operator in five levels of engine speeds...

Introduction Typically, MR-Elastography (MRE) encodes the propagation of monochromatic acoustic waves in the MR-phase images via sinusoidal gradients characterized by a detection frequency equal to the frequency of the mechanical vibration [1]. Therefore, the echo time of a conventional MRE sequence is typically longer than the vibration period, which is critical for heart tissue exhibiting a s...

The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was conducted in order to determine the free vibration characteristics. Natural frequencies and vibration mode shapes were obtained via measurement in LMS Test. Lab. The frequency respo...

Time-varying vocal folds vibration information is of crucial importance in speech processing, and the traditional devices to acquire speech signals are easily smeared by the high background noise and voice interference. In this paper, we present a non-acoustic way to capture the human vocal folds vibration using a 24-GHz portable auditory radar. Since the vocal folds vibration only reaches seve...

with the prolonged use of domestic centrifugal pump, due to erosion, corrosion and an unbalance the sever vibration of the pump are resulted. an erratic sound coming out of pump makes the user uncomfortable. here, tuned vibration absorber (tva) is used as a vibration controlling device. it is designed to reduce the rms velocity below 20% of the circumferential speed, at which the impeller is ba...

OBJECTIVE Low-amplitude whole-body vibration has been adopted for the treatment of back pain and spinal disorders. However, there is limited knowledge of the impact of vibration on the intervertebral disc (IVD). This study was undertaken to examine the effects of acute vibration on anabolic and catabolic pathways in the IVD and to characterize the dependence of these changes on time and frequen...

A robust vibration absorber reduces vibrations of a system over a range of frequencies. Passive vibration absorption is achieved with a tuned mass and spring (known as a dynamic vibration absorber (DVA)). This is a simple, low cost method of reducing vibrations at a single frequency; however, in order to achieve robust absorption a heavy mass is required. Active vibration control is achieved wi...

Objective(s):To study the effect of low-frequency vibration on bone marrow stromal cell differentiation and potential bone repair in vivo. Materials and Methods:Forty New Zealand rabbits were randomly divided into five groups with eight rabbits in each group. For each group, bone defects were generated in the left humerus of four rabbits, and in the right humerus of the other four rabbits. To t...

extremely low frequency (elf) and radio frequency (rf) electromagnetic field may affect biological systems by raising generation free radicals by decline activities of glutathione peroxidase dismutase or increase in the lifetime of free radicals with inhibited pretreatment of cells antioxidant like that alpha tocopherol. elf and  rf electromagnetic  field maycan damaged dna  with raising level ...

A pilot study investigating the influence of vibration during press ups on myoelectrical activity of both dynamic and stabiliser muscles. Nine male participants (21.1 ± 3.4 years, 1.68 ± 0.03 m, 72.3 ± 9.5 kg), performed press ups under 3 conditions: without vibration, low amplitude and frequency vibration (30L; 1.2 mm, 30 Hz) high amplitude and frequency vibration (40H; 1.9 mm, 40 Hz). Press u...