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Vasile Pancotan
Revista Roman? de Kinetoterapie , 2011,
Abstract: The purpose of this study is to emphasize the therapeutic value of mechanical vibrations. It is known that the Health Service, after studying their effect on the health of operators, incriminates the effect of vibrations and imposes a series of rules regarding the limitation of their pathogen effect on people’s health and also on the environment. In these cases the mechanical vibrations are considered to be noxae because of long-term exposure. From the studies on people exposed to vibrations also results that these have also benefic effects, depending on the control of their parameters: frequency, amplitude, time and the particular way of applying them on the human body.There are well known vibration-producing appliances on the market which are addressed to the muscle tonifiation or relaxation, in body-building or even in medical treatment as bronchial drainage, osteoporosis etc. The use of mechanical vibrations for the optimization of the intervertebral disc’s functions in the pathology of the degenerative diseases of the spine is a new idea and has become a wide research field on the different mobile areas of the spine. In order to do so we have tested the input of low and medium frequency mechanical vibrations for pain management in dorsal rheumatic affections as compared to the kinetic treatment in order to quantify the separate role of each form of treatment to find out their exact input.
Longitudinal vibrations of mechanical systems with the transportation effect  [PDF]
A. Buchacz,S. ?ó?kiewski
Journal of Achievements in Materials and Manufacturing Engineering , 2009,
Abstract: Purpose: this thesis purpose is a new way of modelling systems working with high speeds of mechanisms. Systems are analyzed with taking into consideration the rotational movement and with criterions of using materials with high flexibility and high precision of work. The dynamical analysis was done with giving into consideration the interaction between working motion and local vibrations. During the motion a model is loaded by longitudinal forces.Design/methodology/approach: equations of motion were derived by the Lagrange method, with generalized coordinates and generalized velocities assumed as orthogonal projections of individual quantities of the rod and manipulators to axes of the global reference frame.Findings: the model of longitudinally vibrating systems in plane motion was derived, after that the model can be transformed to the dynamical flexibility of these systems. Derived equations are the beginning of analysis of complex systems, especially can be used in deducing of the substitute dynamical flexibility of multilinked systems in motion.Research limitations/implications: mechanical systems vibrating longitudinally in terms of rotation were considered in this thesis. Successive problem of the dynamical analysis is the analysis of systems in spatial transportation and systems loaded by transversal forces.Practical implications: effects of presented calculations can be applied into machines and mechanisms in transportation such as: high speed turbines, wind power plant, water-power plants, manipulators, aerodynamics issues, and in different rotors etc.Originality/value: the contemporary analysis of beams and rods were made in a separate way, first working motion of the main system and next the local vibrations. A new way of modelling took into consideration the interaction between those two displacement. There was defined the transportation effect for models vibrating longitudinally in this paper.
Benefits of Whole-Body Vibration with an Oscillating Platform for People with Multiple Sclerosis: A Systematic Review  [PDF]
Sebasti?o David Santos-Filho,Michelle H. Cameron,Mario Bernardo-Filho
Multiple Sclerosis International , 2012, DOI: 10.1155/2012/274728
Abstract: The objective of this work was to investigate the effects of whole-body vibration on people with multiple sclerosis (MS). PubMed, CINAHL and Scopus databases were systematically searched for studies on the use of whole-body vibration (WBV) exercise in people with MS. These searches were supplemented with material identified in the references and in the authors’ personal files. A qualitative analysis was performed to summarize the findings. Five studies with a total of seventy-one subjects were identified. All of these studies had small numbers of subjects (3–25), and two of the studies had no control groups. Some investigations have shown significant improvements of the muscle strength, of the functional mobility, and of the timed get up and go test in patients with MS. The number of publications found in the databanks searched is small, and in general, they have limitations in the design of protocols with a weakness to the interpretation of the findings. However, the analysis of the findings in these studies permits to conclude that some papers indicate that WBV exercises could benefit patients with MS. In addition, we suggest further larger scale investigations with controlled parameters and well-designed protocols into the effects of WBV exercises in people with MS. 1. Introduction Multiple sclerosis (MS) is a complex, progressive inflammatory, degenerative, and autoimmune demyelinating disease of the central nervous system (CNS) [1, 2] that causes a wide range of signs and symptoms. The most common signs and symptoms of MS are sensory changes, fatigue, balance disturbances, gait problems, spasticity, motor weakness, and impaired muscular performance [2–4]. Various forms of exercise training have been found to be well tolerated and to improve symptoms in people with MS [5, 6]. Traditionally, these programs have focused on aerobic exercise and resistance training, but, over the last several years, whole-body vibration (WBV) has become increasingly popular as a method of exercise both for people with neurological disorders [7–18] and for the general population [19]. WBV is generated when vibrations produced in an oscillating platform are transferred to a human body or parts of it [20]. It is suggested that the consequences in the body could be due to direct or indirect effects [21]. The indirect effects would be associated with neuroendocrine responses [22]. In the direct effect, muscles and tendons act spring-like elements that store and release mechanical energy, as the vibrations [20]. These facts would induce involuntary muscle contractions that
Holistic processing of human body postures: Evidence from the composite effect  [PDF]
Sam Willems,Leia Vrancken,Filip Germeys,Karl Verfaillie
Frontiers in Psychology , 2014, DOI: 10.3389/fpsyg.2014.00618
Abstract: The perception of socially relevant stimuli (e.g., faces and bodies) has received considerable attention in the vision science community. It is now widely accepted that human faces are processed holistically and not only analytically. One observation that has been taken as evidence for holistic face processing is the face composite effect: Two identical top halves of a face tend to be perceived as being different when combined with different bottom halves. This supports the hypothesis that face processing proceeds holistically. Indeed, the interference effect disappears when the two face parts are misaligned (blocking holistic perception). In the present study, we investigated whether there is also a composite effect for the perception of body postures: Are two identical body halves perceived as being in different poses when the irrelevant body halves differ from each other? Both a horizontal (i.e., top-bottom body halves; Experiment 1) and a vertical composite effect (i.e., left-right body halves; Experiment 2) were examined by means of a delayed matching-to-sample task. Results of both experiments indicate the existence of a body posture composite effect. This provides evidence for the hypothesis that body postures, as faces, are processed holistically.
Suppression of friction by mechanical vibrations  [PDF]
Rosario Capozza,Andrea Vanossi,Alessandro Vezzani,Stefano Zapperi
Physics , 2009, DOI: 10.1103/PhysRevLett.103.085502
Abstract: Mechanical vibrations are known to affect frictional sliding and the associated stick-slip patterns causing sometimes a drastic reduction of the friction force. This issue is relevant for applications in nanotribology and to understand earthquake triggering by small dynamic perturbations . We study the dynamics of repulsive particles confined between a horizontally driven top plate and a vertically oscillating bottom plate. Our numerical results show a suppression of the high dissipative stick-slip regime in a well defined range of frequencies that depends on the vibrating amplitude, the normal applied load, the system inertia and the damping constant. We propose a theoretical explanation of the numerical results and derive a phase diagram indicating the region of parameter space where friction is suppressed. Our results allow to define better strategies for the mechanical control of friction.
Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer  [PDF]
Frank B?hnke,Theodor Bretan,Stefan Lehner,Tobias Strenger
Materials , 2013, DOI: 10.3390/ma6104675
Abstract: The transfer characteristic of the human middle ear with an applied middle ear implant (floating mass transducer) is examined computationally with a Multi-body System approach and compared with experimental results. For this purpose, the geometry of the middle ear was reconstructed from μ-computer tomography slice data and prepared for a Multi-body System simulation. The transfer function of the floating mass transducer, which is the ratio of the input voltage and the generated force, is derived based on a physical context. The numerical results obtained with the Multi-body System approach are compared with experimental results by Laser Doppler measurements of the stapes footplate velocities of five different specimens. Although slightly differing anatomical structures were used for the calculation and the measurement, a high correspondence with respect to the course of stapes footplate displacement along the frequency was found. Notably, a notch at frequencies just below 1 kHz occurred. Additionally, phase courses of stapes footplate displacements were determined computationally if possible and compared with experimental results. The examinations were undertaken to quantify stapes footplate displacements in the clinical practice of middle ear implants and, also, to develop fitting strategies on a physical basis for hearing impaired patients aided with middle ear implants.
Effect of the Environmental Stimuli upon the Human Body in Winter Outdoor Thermal Environment  [PDF]
Yoshihito Kurazumi,Emi Kondo,Jin Ishii,Tomonori Sakoi,Kenta Fukagawa,Zhecho Dimitrov Bolashikov,Tadahiro Tsuchikawa,Naoki Matsubara,Tetsumi Horikoshi
Journal of Environmental and Public Health , 2013, DOI: 10.1155/2013/418742
Abstract: In order to manage the outdoor thermal environment with regard to human health and the environmental impact of waste heat, quantitative evaluations are indispensable. It is necessary to use a thermal environment evaluation index. The purpose of this paper is to clarify the relationship between the psychological thermal responses of the human body and winter outdoor thermal environment variables. Subjective experiments were conducted in the winter outdoor environment. Environmental factors and human psychological responses were measured. The relationship between the psychological thermal responses of the human body and the outdoor thermal environment index ETFe (enhanced conduction-corrected modified effective temperature) in winter was shown. The variables which influence the thermal sensation vote of the human body are air temperature, long-wave thermal radiation and short-wave solar radiation. The variables that influence the thermal comfort vote of the human body are air temperature, humidity, short-wave solar radiation, long-wave thermal radiation, and heat conduction. Short-wave solar radiation, and heat conduction are among the winter outdoor thermal environment variables that affect psychological responses to heat. The use of thermal environment evaluation indices that comprise short-wave solar radiation and heat conduction in winter outdoor spaces is a valid approach. 1. Introduction Much research relating to the control of air conditioning systems for living environments and office spaces has been performed but that on outdoor spaces is incomplete. It has been shown that, in addition to physical and physiological environmental factors, psychological environmental stimuli are also important for the determination of thermal comfort. In contrast to indoor spaces, it is not just the thermal environment stimuli but also the environmental complex consisting of visual and auditory stimuli that has an influence on comfort. Adaptation to the thermal environment according to cultural background, experience of being in hot/cold thermal environments and the like, sense of expectation of the thermal environment, behavioural thermal regulation, and the effect of thermal environment history such as the time spent exposed to it are strongly apparent [1–8]. Although thermal comfort is the subject of research, it is treated as nonspecific and comprehensive rather than particular [9]. In the case of restricting the responses to thermal stimuli in instructions for the experiment and not having subjects respond on thermal sense, a nonspecific evaluation is a
Whole-Body Vibrations Do Not Elevate the Angiogenic Stimulus when Applied during Resistance Exercise  [PDF]
?sa Beijer, André Rosenberger, Birgit B?lck, Frank Suhr, J?rn Rittweger, Wilhelm Bloch
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080143
Abstract: Knowledge about biological factors involved in exercise-induced angiogenesis is to date still scanty. The present study aimed to investigate the angiogenic stimulus of resistance exercise with and without superimposed whole-body vibrations. Responses to the exercise regimen before and after a 6-week training intervention were investigated in twenty-six healthy male subjects. Serum was collected at the initial and final exercise sessions and circulating levels of matrix metalloproteinases (MMP) -2 and -9, Vascular Endothelial Growth Factor (VEGF) and endostatin were determined via ELISA. Furthermore, we studied the proliferative effect of serum-treated human umbilical vein endothelial cells in vitro via BrdU-incorporation assay. It was found that circulating MMP-2, MMP-9, VEGF and endostatin levels were significantly elevated (P<0.001) from resting levels after both exercise interventions, with higher post-exercise VEGF concentrations in the resistance exercise (RE) group compared to the resistive vibration exercise (RVE) group. Moreover, RE provoked increased endothelial cell proliferation in vitro and higher post-exercise circulating endostatin concentrations after 6 weeks of training. These effects were elusive in the RVE group. The present findings suggest that resistance exercise leads to a transient rise in circulating angiogenic factors and superimposing vibrations to this exercise type might not further trigger a potential signaling of angiogenic stimulation in skeletal muscle.
The Regenerative Vibrations Influence on the Mechanical Actions in Turning  [PDF]
Claudiu-Florinel Bisu,Raynald Laheurte,Alain Gérard,Jean-Yves K'Nevez
Physics , 2009,
Abstract: In manufacturing during the cutting process the appearance of vibrations can not be avoided. These vibrations constitute a major obstacle to obtain a greater productivity and a better quality of the workpiece. It is thus necessary to develop models which make it possible to study, the totality of the 3D dynamic phenomena. Thanks to an experimental approach the complete torque of the mechanical actions is measured in the presence of the vibrations during a turning operation. This study makes it possible to analyze the variations of the central axis which is a significant parameter of the vibratory phenomena.
Damping of mechanical vibrations by free electrons in metallic nanoresonators  [PDF]
Ze'ev Lindenfeld,Ron Lifshitz
Physics , 2012, DOI: 10.1103/PhysRevB.87.085448
Abstract: We investigate the effect of free electrons on the quality factor (Q) of a metallic nanomechanical resonator in the form of a thin elastic beam. The flexural and longitudinal modes of the beam are modeled using thin beam elasticity theory, and simple perturbation theory is used to calculate the rate at which an externally excited vibration mode decays due to its interaction with free electrons. We find that electron-phonon interaction significantly affects the Q of longitudinal modes, and may also be of significance to the damping of flexural modes in otherwise high-Q beams. The finite geometry of the beam is manifested in two important ways. Its finite length breaks translation invariance along the beam and introduces an imperfect momentum conservation law in place of the exact law. Its finite width imposes a quantization of the electronic states that introduces a temperature scale for which there exists a crossover from a high-temperature macroscopic regime, where electron-phonon damping behaves as if the electrons were in the bulk, to a low-temperature mesoscopic regime, where damping is dominated by just a few dissipation channels and exhibits sharp non-monotonic changes as parameters are varied. This suggests a novel scheme for probing the electronic spectrum of a nanoscale device by measuring the Q of its mechanical vibrations.
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