Search results for "Elastic"
showing 10 items of 2162 documents
Capturing shock waves in inelastic granular gases
2005
Shock waves in granular gases generated by hitting an obstacle at rest are treated by means of a shock capturing scheme that approximates the Euler equations of granular gas dynamics with an equation of state (EOS), introduced by Goldshtein and Shapiro [J. Fluid Mech. 282 (1995) 75-114], that takes into account the inelastic collisions of granules. We include a sink term in the energy balance to account for dissipation of the granular motion by collisional inelasticity, proposed by Haff [J. Fluid Mech. 134 (1983) 401-430], and the gravity field added as source terms. We have computed the approximate solution to a one-dimensional granular gas falling on a plate under the acceleration of grav…
Lock-In Signal Post-Processing Techniques in Infra-Red Thermography for Materials Structural Evaluation
2013
This paper describes the potential of off-line thermographic signal processing by means of Lock-In Correlation algorithms, in order to implement structural health monitoring and stress analysis techniques. Thermal datasets acquired by infrared thermocameras are locked-in and correlated numerically with opportune reference signals, and amplitude and phase values of various harmonics retrieved by means of a Fast Fourier Transform and time averaging based filtering. This information is then processed for NDT defect probing and for evaluating the Thermoelastic Effect induced temperature changes. Two case studies in particular are discussed, implementing the proposed signal lock-in processing: a…
Quantitative thermoelastic stress analysis by means of low-cost setups
2020
Abstract A low-cost Thermoelastic Stress Analysis (TSA) experimental setup is proposed which uses an ordinary micro-bolometer and in-house developed signal processing scripts. The setup is evaluated by analysing the thermoelastic signal from a tensile and a SENT specimen made of stainless steel AISI 304L, and the bolometer performances are compared with those of a state of the art photon detector. Signal processing is based on off-line cross-correlation, using a self-reference signal which is retrieved from the acquired thermal data. Procedures are in particular developed to recognise, quantify and correct errors due to spectral leakage and loss of streamed frames. The thermoelastic signal …
Determination of molecular stopping cross section of 12C, 16O, 28Si, 35Cl, 58Ni, 79Br, and 127I in silicon nitride
2015
Abstract Silicon nitride is a technologically important material in a range of applications due to a combination of important properties. Ion beam analysis techniques, and in particular, heavy ion elastic recoil detection analysis can be used to determine the stoichiometry of silicon nitride films, which often deviates from the ideal Si3N4, as well as the content of impurities such as hydrogen, even in the presence of other materials or in a matrix containing heavier elements. Accurate quantification of IBA results depends on the basic data used in the data analysis. Quantitative depth profiling relies on the knowledge of the stopping power cross sections of the materials studied for the io…
The effects of intensity, frequency, static load, and shore hardness on different parameters in vibration sensitivity measurements.
1987
The effects of shore hardness, static load, frequency, and intensity of vibration on the amplitude and dynamic force effects of vibration were studied in conditions corresponding to those occurring in vibrotactile sensitivity measurements. The measurements were performed on three silicon plates of known shore hardness. The results indicated that the effect of differences in elasticity on the vibration amplitudes was evident at lower frequencies up to about 200 Hz whereas at higher frequencies the amplitudes remained at the same level, regardless of elasticity. On dynamic force the effect of elasticity was observed at all frequencies studied (50-500 Hz). The static load of the contractor had…
"Table 2" of "Quasi-free Compton Scattering and the Polarizabilities of the Neutron"
2003
Energy dependence of the quasi-free proton differential cross section.
"Table 5" of "Quasi-free Compton Scattering and the Polarizabilities of the Neutron"
2003
Energy dependence of the free neutron differential cross section.
"Table 1" of "Compton scattering by the proton through Theta(CMS) = 75-degrees and 90-degrees in the Delta resonance region"
1997
No description provided.
"Table 2" of "Compton scattering by the proton through Theta(CMS) = 75-degrees and 90-degrees in the Delta resonance region"
1997
No description provided.
"Table 1" of "Quasi-free Compton Scattering and the Polarizabilities of the Neutron"
2003
Energy dependence of the free-proton differential cross section.