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A need for vibration isolation in neonatal transport cart is recognized by the medical community. This study is a first step in the feasibility analysis and design of such vibration isolation system. For this application, an effec...
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A need for vibration isolation in neonatal transport cart is recognized by the medical community. This study is a first step in the feasibility analysis and design of such vibration isolation system. For this application, an effective system can be defined as an isolation unit that reduces the level of vibration and mechanical shock experienced by the patient. A goal of this work is to provide the patient with a higher quality level of care relative to the existing neonatal transport system. Insight into the design of a vibration isolation system for a neonatal transport cart is presented with a simple 2 dof system model. The vibration isolation is done by adding air-spring-based passive and active systems. The air springs stiffness is a nonlinear function of pressure. Parametric studies performed with these models show that a passive isolation system provides stable dynamic behavior without sufficient damping. It is shown that with suitable combination of these parameters an effective vibration isolation of the neonatal transport cart is possible thus providing better quality of care. (c) 2004 Elsevier Ltd. All rights reserved.
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While whole body vibration (WBV) levels on North American locomotives are low, it has been suggested that isolated shocks and impacts in the overall vibration environment may pose greater health risks for crew members. In this pap...
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While whole body vibration (WBV) levels on North American locomotives are low, it has been suggested that isolated shocks and impacts in the overall vibration environment may pose greater health risks for crew members. In this paper, the shock and impacts measured on locomotives are evaluated through the vibration dose value (VDV) and spinal stress methods given in international standard ISO2631. More than 90 h of measurement data are used in this analysis. This analysis found that shock and impact present a low probability of adverse health effects. For this data, the health guidance provided in ISO2631 for the VDV is more stringent than the health guidance for the spinal stress. The effects of occupant motion and other data artifacts are also discussed. (C) 2008 Elsevier Ltd. All rights reserved.
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THE PAPER DEALS WITH AN ORIGINAL METHODOLOGY FOR MODELLING and control system design of the semi-active and active systems. At first a generalised simulation model of the vibration reduction system is formulated in such a way that...
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THE PAPER DEALS WITH AN ORIGINAL METHODOLOGY FOR MODELLING and control system design of the semi-active and active systems. At first a generalised simulation model of the vibration reduction system is formulated in such a way that it represents the dynamics of human body exposed to mechanical vibration. Then a novel control system design is proposed in order to adjust force characteristics of the fundamental elements included in the suspension system and consequently to reduce the harmful effects of vibration. Finally, a computational method is experimentally verified by selecting the vibro-isolation properties of an exemplary horizontal seat suspension for a specific input vibration.
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Vehicle manufacturers are continuously seeking to improve vibration comfort. In this paper, subjective responses from transient vibrations in a forklift were analyzed on the basis of ISO 2631-1 and a number of additional variables...
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Vehicle manufacturers are continuously seeking to improve vibration comfort. In this paper, subjective responses from transient vibrations in a forklift were analyzed on the basis of ISO 2631-1 and a number of additional variables. The objectives were to define: the effect of different operating conditions and appropriate background variables of subjects on perceived motions; the development of model that describes perceived discomfort as a function of measured vibrations; and important frequencies for prediction of vibration discomfort. The experiment was based on 12 different operating conditions defined by the variables: vehicle speed, obstacle height and load conditions. Eleven professional drivers participated and their responses of overall discomfort were defined by a vector sum of three perceived motions: shaking, for-aft and up-down motions. The evaluation method, maximum transient vibration value as defined in ISO 2631-1 was found to be adequate in predicting vibration discomfort during a four second transient vibration exposure. By analysis of narrow frequency band spectra of vibrations several explanations for the test results are discussed. The best results were obtained using a prediction model based on accelerations in 1/3-octave bands of pitch vibrations. (c) 2004 Elsevier Ltd. All rights reserved.
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Adult attention deficit hyperactivity disorder (ADHD) is associated with a variety of cognitive impairments, which were shown to affect academic achievement and quality of life. Current treatment strategies, such as stimulant drug...
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Adult attention deficit hyperactivity disorder (ADHD) is associated with a variety of cognitive impairments, which were shown to affect academic achievement and quality of life. Current treatment strategies, such as stimulant drug treatment, were demonstrated to effectively improve cognitive functions of patients with ADHD. However, most treatment strategies are associated with a number of disadvantages in a considerable proportion of patients, such as unsatisfactory effects, adverse clinical side effects or high financial costs. In order to address limitations of current treatment strategies, whole-body vibration (WBV) might represent a novel approach to treat cognitive dysfunctions of patients with ADHD. WBV refers to the exposure of the whole body of an individual to vibration and was found to affect physiology and cognition. In the present study, WBV was applied on 10 consecutive days to an adult diagnosed with ADHD. Neuropsycholog-ical assessments were performed repeatedly at three different times, i.e., the day before the start of the treatment, on the day following completion of treatment and 14 days after the treatment have been completed (follow-up). An improved neuropsychological test performance following WBV treatment points to the high clinical value of WBV in treating patients with neuropsychological impairments such as ADHD.
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The mechanical impedance of the human body in sitting posture and vertical direction was measured during different experimental conditions, such as vibration level (0.5-1.4 m/s{sup}2), frequency (2-100 Hz), body weight (57-92 kg),...
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The mechanical impedance of the human body in sitting posture and vertical direction was measured during different experimental conditions, such as vibration level (0.5-1.4 m/s{sup}2), frequency (2-100 Hz), body weight (57-92 kg), relaxed and erect upper body posture. The outcome shows that impedance increases with frequency up to a peak at about 5 Hz after which it decreases in a complex manner which includes two additional peaks. The frequency at which the first and second impedance peak occurs decreases with higher vibration level. Erect, compared with relaxed body posture resulted in higher impedance magnitudes and with peaks located at somewhat higher frequencies. Heavy persons show higher impedance magnitudes and peaks at lower frequencies.
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This study aimed to determine the impact of multiple doses of whole-body vibration on heel strike, spatial and temporal gait parameters, and ankle range of motion of children with idiopathic toe walking. Whole-body vibration was a...
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This study aimed to determine the impact of multiple doses of whole-body vibration on heel strike, spatial and temporal gait parameters, and ankle range of motion of children with idiopathic toe walking. Whole-body vibration was applied for 5 sets of 1 minute vibration/1 minute rest. Gait measures were collected pre intervention, 1, 5, 10, and 20 minutes postintervention with the GaitRite((R)) electronic walkway. Ankle range of motion was measured preintervention, immediately postintervention, and 20 minutes postintervention. The mean (SD) age of the 15 children (n = 10 males) was 5.93 (1.83) years. An immediate increase in heel contact (P = .041) and ankle range of motion (P = .001 and P = .016) was observed. These changes were unsustained 20 minutes postvibration (P > .05). The gait improvement from whole-body vibration could potentially be due to a rapid increase in ankle range of motion or a neuromodulation response.
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Body vibrations training has become popular in sports training, fitness activity, it is still a rare form of physical rehabilitation.. Vibrations are transmitted onto the whole body or some body parts of an exercising person via a...
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Body vibrations training has become popular in sports training, fitness activity, it is still a rare form of physical rehabilitation.. Vibrations are transmitted onto the whole body or some body parts of an exercising person via a vibration platform subjected to mechanical vertical vibrations. During the training session a participant has to maintain his body position or do exercises that engage specific muscles whilst vibrations of the platform are transmitted onto the person's body. This paper is the continuation of the earlier study covering the effects of low-frequency vibrations on selected physiological parameters of the human body. The experiments were conducted to find the answer to the question if vibration exposure (total duration of training sessions 6 hours 20 min) should produce any changes in hepatic profile of blood. Therefore a research program was undertaken at the University of Science and Technology AGH - UST to investigate the effects of low-frequency vibration on selected parameters of hepatic profile of human blood. Cyclic fluctuations of bone loading were induced by the applied harmonic vibration 3.5Hz and amplitude 0.004 m. The experiments utilizing two vibrating platforms were performed in the Laboratory of Structural Acoustics and Biomedical Engineering AGH-UST. The applied vibrations were harmless and not annoying, in accordance with the standard PN-EN ISO 1309011, 1998. 23 women volunteers had 19 sessions on subsequent working days, at the same time of day. during the tests the participants remained in the standing position, passive. The main hypothesis has it that short-term low-frequency vibration exposure might bring about the changes of the hepatic profile of blood, including: bilirubin (BILIRUBIN), alkaline phosphatase (Alp), alamne aminotransferase (ALT), aspartate aminotransferase (AST) and albumin (ALBUMIN) levels. Research data indicate the low-frequency vibrations exposure produces statistically significant decrease of bilirubin level [umol/l] in blood serum from 14.05 to 9.70 for 82% of participants, the probability level being p = 0.000041.
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Whole-body vibration (WBV) training is a very popular kind of practice in sport, fitness and physiotherapy. This work reviews the current knowledge regarding the use and effectiveness of WBV in the physiotherapy. The discrepancies...
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Whole-body vibration (WBV) training is a very popular kind of practice in sport, fitness and physiotherapy. This work reviews the current knowledge regarding the use and effectiveness of WBV in the physiotherapy. The discrepancies between different authors' results are probably due to divergence in WBV training protocols. The paperwork clearly showed that despite its ultimate effects, exercises on a vibration platform are safe, feasible, and well tolerated by patients with different disorders. This narrative review should help physiotherapists verify therapy programs regarding patients' exposure to WBV.
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Horizontal whole-body vibration (WBV) can have an influence on health and comfort of drivers. Driver seats with additional suspensions in x- and/or y-axis should reduce the influence of vibration on the driver. No standards or tes...
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Horizontal whole-body vibration (WBV) can have an influence on health and comfort of drivers. Driver seats with additional suspensions in x- and/or y-axis should reduce the influence of vibration on the driver. No standards or test procedures are available for testing seats with horizontal suspensions. A standard test procedure for seats with horizontal suspensions could be developed from a test protocol used in a recent inter-laboratory study. To reduce the variability of the results obtained by different laboratories or repetitions, the test procedures should carefully consider methodological aspects with relevance to the results. Specifications of typical signals obtained in practice, or well-defined random time series as a basis for generation of test signals, with defined signs of acceleration would enable identical excitations in time domain and could reduce the variability of results caused by the non-linearity of the seat-human system. Nine healthy subjects volunteered for the study to test a seat with suspensions in three directions. They were selected with regard to three groups of body mass (52.4-54.6, 75.5-77.1, 98-100.7 kg). A random signal and two signals obtained in practice (tractor and truck) were selected for excitations in x- and y-directions by a six DOF electro-hydraulic simulator (hexapod). The errors between the desired and measured accelerations were calculated. The error depends on the signal, the direction and the subject. In the time domain, the absolute value of the error ranged from 1.8% to 42.4%. The SEAT value generally depends on the body mass, but in some cases the SEAT value of a lighter subject was lower than the SEAT value of a heavy one. This indicates that only one heavy and one light subject are not suited to calculate reliable parameters for an evaluation and comparison of seats. The non-symmetric displacements of the seat frame in x-direction indicate the non-linear behaviour of the seat-subject system.
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