Search results for "vibration"
showing 10 items of 823 documents
Magnetic Stochastic Resonance in systems described by Dynamic Preisach Model
2008
Stochastic resonance (SR) is generally considered as an enhancement of the system response for certain finite values of the noise strength. In particular the signal to noise ratio (SNR) and the signal amplification show a maximum as a function of the noise intensity. This effect has been experimentally observed in many physical systems and also in magnetic systems. However, as far as magnetic systems are concerned, the dynamic features of the systems have been neglected and it has been assumed that the typical relaxation time is negligible. However this is clearly a rough approximation. In order to clarify this relation, in this paper we numerically study magnetic stochastic resonance in se…
Sorveglianza sanitaria su un gruppo di lavoratori esposti a vibrazioni mano-braccio
2007
Nei lavoratori esposti a rischio da vibrazioni mano-braccio è indispensabile un’efficace sorveglianza sanitaria in linea con la recente normativa in materia, a garanzia della salute e della sicurezza nei luoghi di lavoro. In particolare abbiamo esaminato un gruppo di soggetti addetti alla manutenzione di aree verdi applicando le linee guida più recenti e la vigente normativa in tema di prevenzione(1,3) . As concerns those workers exposed to a risk of hand-arm vibration, an efficacious sanitary monitoring is necessary, according to recent norms, in order to assure health and secu - rity in workplaces. We have examined a group of people assigned to the maintenance of green spaces, applying th…
UiA Accelerated Life Time Bearing Test Rig – Test 1, 250 rpm
2020
Vibration data from an accelerated lifetime test of a bearing. Contains raw vibration data and shaft position data. The mean shaft speed is 250 rpm. Can be used for fault diagnosis and remaining useful lifetime estimation. Please see "00_ReadMe.pdf" file for more details. Update - 3 January 2022: This dataset is now updated to use floating point values for shaft position data, which gives a much more accurate description of the shaft position.
UiA Accelerated Life Time Bearing Test Rig – Test 3, Variable speed around 50rpm
2021
Vibration data from an accelerated lifetime test of a bearing. Contains raw vibration data and shaft position data. The mean shaft speed is 50rpm with a variation +- 40 rpm. Can be used for fault diagnosis and remaining useful lifetime estimation. Please see "00_ReadMe.pdf" file for more details.
Short hydrogen bonds enhance non-aromatic protein-related fluorescence
2020
AbstractFluorescence in biological systems is usually associated with the presence of aromatic groups. Here, we show that specific hydrogen bonding networks can significantly affect fluorescence employing a combined experimental and computational approach. In particular, we reveal that the single amino acid L-glutamine, by undergoing a chemical transformation leading to the formation of a short hydrogen bond, displays optical properties that are significantly enhanced compared to L-glutamine itself. Ab initio molecular dynamics simulations highlight that these short hydrogen bonds prevent the appearance of a conical intersection between the excited and the ground states and thereby signific…
Effects Of Whole Body Vibration In Patients With Chronic Obstructive Pulmonary Disease - A Randomized Controlled Trial
2012
Summary Introduction To date endurance and strength training are established and evidence-based exercise methods in patients with chronic obstructive pulmonary disease (COPD). There is an unmet need for further research in new and complementary exercise modalities. Additional whole body vibration training during pulmonary rehabilitation may be such a new approach that has not yet been investigated in patients with COPD. Methods Eighty-two patients (65 ± 9 yrs, FEV 1 pred. 38 ± 11%, female 51%) with COPD in GOLD stage III to IV assessed for a 3-week inpatient multidisciplinary rehabilitation program were on top randomly assigned to one of two intervention groups: (1) 3 × 3 min of bilateral d…
Intermolecular potential and rovibrational states of the H2O–D2 complex
2012
International audience; A five-dimensional intermolecular potential for H2O-D-2 was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedzuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H2O and D-2. On this five-dimensional potential with a well depth D-e of 232.12 cm (1) we calculated the bound rovibrational levels of H2O-D-2 for total angular momentum J = 0-3. The method used to compute the rovibrational levels is similar to a scattering approach-it involves a basis of coupled free rotor wave functions for the hindered internal r…
Spherical top data system (STDS) software for the simulation of spherical top spectra
1998
Abstract The Spherical Top Data System (STDS) software package for the simulation of spherical top spectra is presented. It consists of a single UNIX script with self-explanatory arguments allowing the non-expert user to calculate spectra from the results of the high resolution analyses performed over the recent decades on this type of molecules. More than one hundred parameter files are presently available including various band systems of 16 molecular species (among which methane is the most documented) and various types of calculations: rovibrational energy levels, i.r. absorption, Raman scattering and Stark coefficients. STDS is freely accessible by anonymous ftp at jupiter.u-bourgogne.…
Experimental Investigation of the Modal Response of a Rail Span during and after Wheel Passage
2020
This paper examines the vibrations of a rail span (rail section between two consecutive sleepers) during and after the passage of a rail car’s wheel as well as under impact hammer excitation. In literature, the dynamic response of railway tracks under moving loads has been studied extensively. Many of these studies focus on the responses in relation to displacement/force-time histories and wave propagation parameters. These responses are investigated for the time instants when rail car wheels transverse over the rail spans of interest. In this context, an investigation of responses in relation to modal parameters during and after moving loads might provide additional information. Such info…
Unveiling the role of the lone electron pair in sesquioxides at high pressure: compressibility of β-Sb2O3
2021
The structural, vibrational and electronic properties of the compressed beta-Sb2O3 polymorph, a.k.a. mineral valentinite, have been investigated in a joint experimental and theoretical study up to 23 GPa. The compressibility of the lattice parameters, unit-cell volume and polyhedral unit volume as well as the behaviour of its Raman- and IR-active modes under compression have been interpreted on the basis of ab initio theoretical simulations. Valentinite shows an unusual compressibility up to 15 GPa with four different pressure ranges, whose critical pressures are 2, 4, and 10 GPa. The pressure dependence of the main structural units, the lack of soft phonons, and the electronic density char…