To understand the basic characteristics of the human body vibration induced by low frequency noise and to use it to evaluate the effects on health, we designed a measuring method with a miniature accelerometer and carried out preliminary measurements. Vibration was measured on the chest and abdomen of 6 male ...

Vibration sonoelastography has been developed for the detection of hard lesions in relatively soft tissue. The basic concept is to propagate low-amplitude and low-frequency shear waves (with displacements below 0.1 mm and frequencies typically below 1000 Hz) through deep organs, and displaying the vibration response in real-time using advanced color ...

Several investigations have revealed that long-term exposure to whole-body vibrations can induce low back pain. In analogy to materials handling, the health risk can be assessed if the forces transmitted in the spine during vibration are known. To estimate the forces a biomechanical model has been developed in which the ...

BACKGROUND: To evaluate the effects of whole body vibration on discomfort, the sensitivity to different frequencies as well as to different vibration axes must be regarded. This experimental study investigates the significance of lateral relative to vertical motions in the sensation of dual axis sinusoidal vibrations in sitting posture. The ...

STATEMENT OF PROBLEM: Numerous factors are involved in making a void-free dental stone cast from a polyvinyl siloxane impression. PURPOSE: The aim of this study was to determine whether frequency and amplitude of vibration had any effect on the formation of voids on the cast surface poured from polyvinyl siloxane ...

The piezoelectric contact sensor has been widely utilised in mechanomyography (MMG). The authors aim to clarify the mechanical variables (i.e. acceleration, velocity or displacement) reflected by the MMG signal detected with a piezoelectric contact sensor (PEC), and compare the results with those obtained simultaneously by an accelerometer (ACC). To measure ...

A novel device, the Sliding Linear Investigative Platform For Analyzing Lower Limb Stability (SLIP-FALLS), has been designed to study the detection and discrimination thresholds of humans to uniaxial horizontal step, ramp, or sinusoidal translations of the surface upon which they stand or stride. The device also can be used to ...

OBJECTIVE: Photoplethysmography utilizes a green-light-emitting diode to transmit light into a tissue. Reflected light from hemoglobin in dermal capillary red blood cells is received by a photo detector and is analyzed as light intensity along a frequency spectrum. This method of analysis allows for the removal of "noise" above (stray ...

Hair bundles on tentacles of sea anemones are similar to vertebrate hair bundles in terms of structure and function. Anemone hair bundles are involved in regulating discharge of nematocysts, "stinging capsules," used to capture prey. N-acetylated sugars from the prey including N-acetylneuraminic acid (NANA) induce hair bundles to elongate while ...

An experimental protocol was tested to measure elastic properties of connective tissue displaying viscoelastic as well as plastic properties. The protocol consisted of a slow rate, linear elongation (0.88 mms(-1), 8 mm) in combination with a superimposed sinusoidal vibration of small amplitude (50 Hz, 0.1 mm). Using digital filters and ...

OBJECTIVE: The aim of the present study was to quantify the sensory and functional effects resulting from a short-duration (30 min) exposure to hand-arm vibration. SUBJECTS AND METHODS: Nine subjects went through nine laboratory experiments. For 32 min they grasped a handle vibrating at three different amplitudes (5, 20, and ...

Male Cystosoma saundersii have a distended thin-walled abdomen which is driven by the paired tymbals during sound production. The insect extends the abdomen from a rest length of 32-34 mm to a length of 39-42 mm while singing. This is accomplished through specialised apodemes at the anterior ends of abdominal ...

Excised gerbil cochleae were cut along the mid-modiolar plane (hemicochlea). Along one-half turn of this preparation, fluorescent microbeads were placed on the basilar membrane (BM). The BM was vibrated with click stimuli (50 micros) produced mechanically by a piezo pusher. The stimulus delivery probe could be positioned either more apical ...

The magnitudes of the hand-transmitted vibration, 297 hand-held tools and workpieces were measured at workplaces. The tools were used mainly in construction and manufacturing industries. The current standard for the measurement of hand-transmitted vibration has been based on the frequency-weighted acceleration of dominant axis method. According to the proposal of ...

Absorbed power (PAbs) during exposure to vertical whole-body vibration in a sitting posture was measured on 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0.5-1.4 m s(-2)) and frequency (2-100 Hz), body weight (54-93 kg) and, relaxed and erected upper body positions. Results ...

The influence of whole-body vibration on gastric motility was investigated by using an electrogastrography (EGG) in seven healthy men. The EGG is usually referred to as a noninvasive technique of recording gastric myoelectrical activity by means of placing electrodes on the abdominal surface. Sinusoidal vertical vibration at each of 3 ...

Understanding of the resonance behaviour of the human body is important in the identification of vibration frequencies and body postures associated with back problems. In this study, experimental modal analysis was applied to whole-body vibration. Eight subjects were exposed to vertical random vibration while adopting three different postures on a ...

To clarify the effects of whole-body vibration (WBV) on visual performance, visual acuity and a self-rated assessment of difficulties in visible perception were determined after various frequencies of vibration in six healthy males. Two different sitting postures, an erect posture and a muscle-relaxed posture, were used. Sinusoidal vertical vibrations at ...

A transducer for an ultrasonic motor using two sandwich-type vibrators has been proposed and designed. The vibrators cross at right angles with each other at the tip. The transducer has two vibration modes; one is a symmetrical mode and the other is anti-symmetric. The normal direction motion of the transducer ...

It generally is known that vibration of various muscles in free-standing subjects evokes a spatially oriented postural response. Furthermore, it recently has been shown that when a vibratory stimulus is terminated, a powerful involuntary contraction of the previously vibrated muscle often occurs that, under the isotonic condition, is accompanied by ...

BACKGROUND: The performance of tasks in which the head must be positioned close to objects in a moving vehicle may be impeded by the presence of vibration. HYPOTHESES: It was hypothesized that the extent to which a head positioning task would be impeded by whole-body vibration would depend on the ...

Late instar larvae and pupae of the spotted tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera: Gracillariidae) react with defensive behaviour when attacked by one of their parasitoids, the eulophid wasp Sympiesis sericeicornis Nees (Hymenoptera: Eulophidae). Vibrations produced during the insertion of the ovipositor into the mine are known to be important ...

This study was designed to determine whether vibration thresholds of transcriptionists varied significantly from the thresholds of individuals not exposed to keyboard activities. Using a multifrequency vibrometer, we obtained vibration threshold values from 31 medical transcriptionists who perform work on computer keyboards and compared them to values obtained from 40 ...

Many forms of industrial illness are thought to result from the effects of vibration on the human body. Prolonged exposure causes undue stress and discomfort. At the human whole-body resonant frequency there is maximum displacement between the organs and the skeletal structure and thus this is one frequency of vibration ...

OBJECTIVES: To investigate changes in digital circulation during and after exposure to hand transmitted vibration. By studying two frequencies and two magnitudes of vibration, to investigate the extent to which haemodynamic changes depend on the vibration frequency, the vibration acceleration, and the vibration velocity. METHODS: Finger skin temperature (FST), finger ...

To study combined effect of noise and vibration on articulation, changes of the speech features of Chinese single syllabic utterances were investigated under combined factors. The experiments were conducted under four conditions: combined noise and vibration, simple noise, simple vibration and control. A set of signal processing system was established, ...

We present an experimental and theoretical analysis of vibration microscopy using an arbitrarily defined detection aperture. For the two limiting cases, incoherent operation (no aperture) offers intensity-gradient information in the amplitude of higher harmonics of the vibration frequency, whereas coherent operation (pinhole aperture) reflects the phase of the object being ...

In order to study the characteristics of human dynamic response to vibration, 56 subjects were exposed to vibration on X, Y and Z axes. It showed that there were two resonance peaks of most local parts of the human body. The curves of transmissibility are essentially the same in all ...

The ECG response of a human body exposed to vertical vibrations was investigated. The per cent normalized difference (PND) between the R-wave amplitude before and after vibrations was monitored. Results obtained from a representative subject show an oscillatory decay of the PND behaviour with time. This behaviour can be modelled ...

Vibration is related to reports of low back pain; however the biomechanics of vibration transmission through the hand-arm system has not been previously studied. Vibration was recorded on an accelerometer mounted to a pin percutaneously imbedded in the spinous process of L4 of five human subjects. The energy was applied ...

The measurement of hand-transmitted vibration converts oscillatory movements to a form in which they can be evaluated with respect to human responses and assessed for their acceptability. This paper presents methods of measurement, evaluation, and assessment currently advocated in standards and other forms of guidance. The degree to which the ...

The continual exposure of outer hair cells (OHCs) to thermal noise causes vibrations in resonant frequency. As these vibrations are backprojected, they should be recordable as audiofrequencies in the outer ear canal. But even though they are likely to be amplified in some areas by clustering in terms of the ...

The present investigation evaluated the effects of changes in pelvic orientation and vibration frequency on the seated human's response to wholebody vibration (WBV). Seat-to-trunk and seat-to-head acceleration transmissibility, peak-to-peak pelvic motion and erector spinae EMG and mean erector spinae EMG was collected across three pelvic orientations (9 degrees anterior pelvic ...

The influence of vibration frequency (40, 80, 100, 120, 150, or 200 Hz) at selected displacement amplitudes (0.2, 0.3 mm) on tonic vibration reflex (TVR) characteristics was investigated. The degree of synchronization of motor unit activity with vibratory stimuli in ten humans was determined using the electromyographic (EMG) activity of ...

Real-time vibration measurement by a tilted holographic interferogram is presented that utilizes the real-time digital fringe processor of a video signal. Three intensity data sampled at every one-third of the fringe spacing of the tilted fringes are used to calculate the modulation term of the fringe that is a function ...

OBJECT: To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects. METHOD AND DESIGN: Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s2, 60 Hz), noise [90 dB(A)] and both, ...

We present a demonstration of mid-infrared photon echoes generated with parametrically downconverted incoherent light. The photon echoes generated in this way enable one to study the dynamics of vibrations in the 1.5-4.0-microm wavelength region with subpicosecond time resolution.

The capability for discrimination of vibratory stimuli of the sole of the foot was tested on 12 subjects (6 men, 6 women). Two vibratory stimuli (sinusoidal impulse: frequency, 200 Hz; amplitude, 0.1 mm; duration, 2 sec) were applied at different sites to the sole of the foot. Subjects were asked ...

We have studied the sound and vibration sensitivity of 164 amphibian papilla fibers in the VIIIth nerve of the grassfrog, Rana temporaria. The VIIIth nerve was exposed using a dorsal approach. The frogs were placed in a natural sitting posture and stimulated by free-field sound. Furthermore, the animals were stimulated ...

We quantified volume and frequency thresholds necessary for the inhibition of respiratory motor output during prolonged normocapnic mechanical ventilation in healthy subjects during wakefulness (n = 7) and NREM sleep (n = 5). Subjects were ventilated at eupneic frequency (fR) with 3 min step-wise increases in tidal volume (VT), or ...

The spontaneous low- and high-frequency rhythms in the sympathetic discharge of decerebrate artificially ventilated cats are affected by external ventilation. Two graphical methods (i.e. the space-time separation plot and the frequency tracking locus) are used to classify the non-linear interactions. The observed behaviours in the sympathetic discharge consist of phase-locked ...

In static posturography, proprioception is often disturbed using vibrators applied bilaterally to the calf muscles. The effect of vibrator amplitude on body sway was compared in static posturography using bilateral vibrators on the calf muscles of 30 healthy male military conscripts at frequencies of 50 and 90 Hz. Postural stability ...

OBJECTIVES: The purpose of this study was to investigate whether two devices for measuring vibrotactile perception thresholds produced similar results on an individual basis and to compare the thresholds in the presence or absence of sensorineural hand symptoms and vibration exposure. METHODS: Vibrotactile perception thresholds were measured with a vibrameter ...

An electrical simulation of a mechanical model of a 60 kg pregnant woman subjected to horizontal and vertical vibrations has been investigated by using a computer software package (MICRO-CAP II). The results have shown that mechanical vibrations affect the body segments differently based on their location, the kind of vibration ...

When operating a hand-held vibrating power tool, for example impact drills and rotary hammers, high vibration loads are introduced into the hand-arm system of the operator. In the long run these mechanical vibrations can lead to health problems of the hand-arm system. Hammer drilling tools for treatment of mineral materials ...

Mechanical vibration of the abdominal wall results in a frequency-related distribution of intra-abdominal sound pressure levels. A greater attenuation of applied signals of equal dynamic force occurs as frequency increases. A broad resonance peak exists between 6 and 18 Hz. Transducers fixed to the fetal head show clear increases in ...

OBJECTIVE: The human body is often exposed to significant vibration stress in the workplace, at home, and during recreational activities. The current study was designed to evaluate whether low- to midfrequency vibrations present at the extraabdominal wall would be attenuated across this wall and what the levels of exposure would ...

Vibration measurements have been done on hand-held tools in a group of 48 platers by evaluating the individual vibration acceleration and absorption of vibration energy. The measurement of acceleration has been done frequency-weighted and frequency-unweighted in accordance with ISO 5349 and NIOSH (USA) recommendations for hand-arm vibration standards, respectively. The ...

Behavioural observations of Nezara viridula suggested that the antennae could be involved in detecting the substrate vibrations important in intraspecific communication of these insects. Therefore the vibrosensitive properties of Johnston's organ, a mechanoreceptor sensitive to the movements of the antennal flagellum relative to pedicel, were investigated. Vibrational stimuli were applied ...

It has been suggested that "double-wound" (bifilar) exposure coils are capable of producing a sham environment in which hum and vibration will be "similar" to the field-exposed condition. We found by direct measurements in a bifilar coil system that vibration amplitude in sham and exposed conditions differed by a factor ...