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In the last decade the vibrations of the whole body(WBV) is the very frequent method of usual neuromuscular training with a wide spread in health or fitness centers and with tendencies to replace the training and the conventional therapy, both in physical therapy and in sports, in order to increase the strength and muscular power. This development is due to the fact that the effects of low amplitude and low frequency vibrations have been found to lead to the development of leg muscle strength, bone strengthening by increasing bone density or improving neuromotor problems. At the same time, the industry has offered, at an affordable price, a wide variety of vibrating platforms, with wide possibilities to adjust the amplitude, the duration of exposure and the frequency of the vibrating movements. This paper tries to explain the biomechanical explanation of the phenomenon of relaxation of the stress state in the muscle-tendon complex after the treatment with vibrations of the whole body. For this purpose, several biomechanical models were analyzed which, following the vibrations of the whole body and after analyzing the response to these stimuli, lead to results that can encourage various experiments.

Swimming pools need some sort of alarm system to indicate if someone or an article have dropped into the water. This article conveys the methods and practices used in the detection and analysis of low frequency vibrations in water for this purpose. Logged data are used to develop a digital signal processing system that is able to distinguish between different vibration signatures to determine the source of the vibration. Conclusions are drawn from the results and the viability of the technology is evaluated.

Based on fiber Bragg grating, we design a low-frequency vibration monitoring system for hydro-generator set Fiber grating sensors are installed in the hydrogenating unit. The vibration signal of the hydro-generator can be acquired. We can judge the running state of hydro-generator unit. The application showed that the fiber grating sensing and monitoring system can timely and accurately report the status of hydrogenating unit.

Several mechanisms of wear can occur in rolling element bearings (REBs). As the wear evolves, the vibration level will increase with the growth of internal clearance of bearings due to the variation of contact force and dynamic excitation. Therefore, for accurate fault severity diagnosis, internal clearance increase caused by inevitable wear has to be taken into account. In this paper, clearance variation caused by the wear of tapered rolling bearings (TRBs) is investigated experimentally and clearance estimation is carried out based on analysis of low frequency vibrations and the deviation of the fault features. An experimental study is ingeniously designed to simulate the wear evolutions and evaluate their influence on well-accepted envelope signatures according to vibrations measured from TRBs. The defective bearings were diagnosed in two aspects: the magnitude variation of vibrations in the low frequency band and the peak frequency deviation. The experimental results give out a signature shift with regard to the wear evolution, also vibration magnitude of the low frequency band grew remarkably. Therefore, unavoidable wear can be estimated and consequently the fault severity diagnosis improved.

A vibration sensor is explored by using multicore fiber to measure particles vibration. Extreme low frequency vibration(1.5Hz-2.0Hz) with resolution of 0.1Hz is achieved. It is a potential method to acquire particles movement information.

In this study, we developed the novel three-dimensional (3D) impact-based microenergy harvesters for harvesting random vibrations from multiple directions. The device consisted of a 3D box built up from the flexible AlN/SUS-based microcantilevers and the free-moving SUS ball. When the ball receives external vibration energy, it might strike the cantilevers on the surrounding walls and then the device generates electricity. The merit of this configuration is the device could generate the electricity from low frequency and multi-directional vibrations. The developed device provided the peak output power 70 nW on average for the triaxial vibrations at the extremely low frequency of 4.5 Hz which frequency regime is very difficult to be harvested by the published microenergy harvesters.

This paper demonstrates a hybrid converter, which, for the first time, combines both the piezoelectric and the electromagnetic mechanisms in a ball-impact structure. The converter can harvest low-frequency vibration energy with an external power and has been proven to work in an environment with the ambient vibration frequency under 10Hz.

Low Frequency Vibration-cutting (LFV) is a new machining technology developed to solve problems with the turning process. Vibration applied to the servo shaft in the feed direction can be synchronized with the rotation spindle. This technology has the significant feature of discharging the chips intermittently, because it has “air-cutting” times during cutting. It also can handle a variety of machining types, and is therefore suitable for cutting difficult-to-cut materials. However, the mechanisms of LFV have not been fully investigated. Therefore, to clarify these mechanisms, cutting tests were conducted on SUS304 to evaluate cutting force, and to compare the cutting properties of LFV with that of conventional cutting (CC). The LFV showed improved effects in terms of a decrease in cutting force. (“LFV” is a registered trademark of Citizen Watch Co., LTD., Japan)

This paper analyzes the influence mechanism of the ship low frequency vibration on the output characteristics of PV cells under direct light and scattered light. And the simulation model in the MATLAB/Simulink platform has been put up, and some related experimental studies have been carried out based on the experiment platform, which can simulate ship vibration environment. The results of the simulation analysis and the experimental study all show that it is possible to lead to slight fluctuation on the output of PV cells and there is no obvious effect on fluctuation range with frequencies of the vibration. The impact effects on the output characteristics of PV cells are different under different solar irradiation.

This paper presents a new combined electrostatic-triboelectric energy harvester. One of the practical limitations of Electrostatic Vibration Energy (EVE) harvesting technologies is the need for an initial priming voltage source. In the proposed scheme, the triboelectric effect is used to provide initial charges necessary for EVE harvester. This harvester converts vibration to electrical energy and stores it in two storage capacitors. The new harvester has a triboelectric part and an EVE part. The triboelectric part charges one of the storage capacitors and at the same time supplies necessary initial charge for EVE part which charges the other storage capacitor. In this way, charges generated by triboelectric part are fully transferred from it, which ensures best and continuous triboelectric charge generation. Without proper transfer of charges, the triboelectric part will saturate in few cycles of vibration. Thus, in the combined harvester both schemes aid each other. A prototype of the new harvester has been built and tested. The developed unit generated about 45 nW of power from a low frequency vibration source of 3 Hz.

The purpose of this study was to use frequency spectrum analysis to determine the effects of skin and muscle on the bone's low frequency vibration signals recorded from vibration sensors placed on the skin. A setup was developed that allowed low frequency vibration signals to be recorded. Tests were performed on a sample of 8 turkey legs in vitro, using four vibration sensors placed on the skin, muscle (i.e. leg with the skin removed) and bone (i.e. leg with skin and muscle removed). It was found that bone's vibration signals could be recorded from sensors placed on the skin, but there were changes in their magnitudes and vibration frequencies. There was also a direct relationship between the main frequency of bone's vibration and its mass/volume ratio. This is a preliminary study. The ultimate aim of this study (to be achieved in further work) is to predict fracture risk and target therapy appropriately.

mechanical vibrations and motions is prove to be one of the key factors that affect dynamic image quality of TDI camera. Degradation models due to mechanical vibrations and motions were established. Based on this model, analyzing image quality acquired by TDI detectors present that mechanical vibrations may cause space-variant image distortions (severe geometric warps and blur) was studied. The results indicate that in the along-scan direction abnormal linear motion and high frequency vibration only cause space-invariant image blur while low frequency vibration result in space-variant image blur and geometric distortions. In the cross-scan direction, no matter which vibration, geometric distortions will be appeared.

In this paper, we introduce a parallel microdroplet mixing strategy based on local acoustic field generation using low frequency vibrations. An active acoustic mixer array was designed and fabricated. This microfluidic device permits the creation in parallel of an active mixture in a matrix of 25 microdroplets that are localized on a surface. It was designed to avoid contamination between droplets while they are excited. Experiments showing the active mixture of droplets will be presented.

The paper present a complex and interdisciplinary research problem specific to the macro drive. It is formulated the problem of incomplete oil recovery of petroleum industry with low frequency vibrations generated with the magnetostrictive actuator systems. So ,are presented initial aspects on medium conditions in relation with the design actuator elements. It is the first paper on this topic and is not exhausted the whole problem I.

There is a general interest in developing a new research field linking new powerful sources of THz radiation with key contemporary challenges in protein science; Specifically, the highly controversial role of fast protein promoting vibrations in biological catalysis. However, the 1-10 THz region of the electromagnetic spectrum is particularly difficult to access experimentally due to the low intensity of conventional laboratory based sources. Therefore we developed a THz radiation station using the existing accelerator based sources on the SRS at Daresbury. We recorded spectra incorporating the low frequency collective vibrations of small molecules as well as some proteins in the solid state. Our experiments were carried out using non-coherent radiation from the modified THz testing facility (TTF) on the SRS at Daresbury.

Sonoelasticity imaging which can display internal low frequency vibration in soft tissue like medium under forced vibration may give a useful information about viscoelastic properties of the tissue. In this paper, a new imaging method which can get high quality images even for in vivo experiments is proposed.