Search results for "FAST"
showing 10 items of 821 documents
Etude d'un emmanchement fretté compte tenu de l'effet combiné des défauts de forme et d'état de surface
2012
The main purpose of this thesis is to present two contributions in the field of shrink fitassembly taking into account the defects of form and roughness surfaces. The first contributionconcerns the study of the influence of the defect forme on the characteristics of shrinked assemblyusing an approach based on finite element modeling. We found that this defect has a significantinfluence on the resistance of the assembly. The work already done in the laboratory of mechanicsat the University of Bourgogne have been confirmed. In the second contribution, we proposed tointegrate the surface defects (roughness) by creating a homogenized finite element interface. Thistechnique has facilitated the m…
Management of Microbiological Quality of Meat in the Context of Rapid Tenderization
2018
Abstract This paper focuses on the study of the microbiological load of pork and beef meat, in the context of utilising fast methods of tenderizing them. The study highlights, through both classic and fast methods, the microbial load of fresh, salted and smoked pork and beef meat. It has been established that fresh pork is at around 7,2x104-8,5x104CFU/g, whereas fresh beef sits at around 2,3x103 CFU/g. For salted, smoked and classically tenderized, these values are between 3,3x104 CFU/g and 4,7x104CFU/g for pork and 6,1x102 CFU/g for beef. The method of rapid tenderizing leads to highlighting a decreased microbial load: 2,2x103 CFU/g-5,4x103CFU/g for pork, 2,8x102 CFU/g for beef, which cons…
Area-efficient FPGA-based FFT processor
2003
A novel architecture for computing the fast Fourier transform on programmable devices is presented. Main results indicate that the use of one CORDIC operator to perform the multiplication by all the ‘twiddle factors’ sequentially leads to an area saving up to 35% with respect to other cores.
A fast BEM for the analysis of damaged structures with bonded piezoelectric sensors
2010
A fast boundary element method for the analysis of three-dimensional solids with cracks and adhesively bonded piezoelectric patches, used as strain sensors, is presented. The piezoelectric sensors, as well as the adhesive layer, are modeled using a 3D state-space finite element approach. The piezoelectric patch model is formulated taking into account the full electro-mechanical coupling and embodying the suitable boundary conditions and it is eventually expressed in terms of the interface variables, to allow a straightforward coupling with the underlying host structure, which is modeled through a 3D dual boundary element method, for accurate analysis of cracks. The technique is computationa…
Frequency-dependent response and dynamic disorder
1991
Abstract This paper discusses selected aspects of the application of dynamic percolation models to ionic transport in mixed-ion superionic conductors. The discussion is based on an AB lattice gas model with hard-core repulsions and a ratio of τ, 0 ⩽ τ ⩽ ∞, between the transition rates of particles A and B. The frequency-dependent conductivity for a tracer particle is calculated within an effective-medium theory. The motion of the background B-particles is regarded as providing a fluctuating disordered environment for the tracer particles A. A crossover frequency separating high-frequency and low-frequency response is found which scales with τ as ω c ∼ τ 1 2 . The results for the dc limit ar…
Radiation defects in undoped and Nd‐doped LaGaO 3 crystals
2005
Radiation induced defects have been studied in undoped and Nd-doped (6 mol% and 12 mol%) LaGaO3 crystals. Wide absorption band (2.2–2.8 eV) was observed after crystal irradiation with X-rays at 300 K. Induced defects have been annealed in air at ∼450 K. Similar absorption band was observed in transient absorption spectra after ns-pulsed electron beam excitation. The radiation defect creation efficiency is higher in undoped LaGaO3 crystal. It is shown that small concentration of Nd-doping increases the LaGaO3 crystal radiation hardness. In transient absorption spectra along with 2.7 eV band the absorption bands at 1.5 eV and 2.2 eV were observed. The decay process of transient absorption has…
Decoupling the artificial special pair to slow down the rate of singlet energy transfer
2012
Trimer 2, composed of a cofacial heterobismacrocycle, octamethyl-porphyrin zinc(II) and bisarylporphyrin zinc(II) held by an anthracenyl spacer, and a flanking acceptor, bisarylporphyrin free-base ( Ar = -3,5-(t Bu )2 C 6 H 3), has been studied by means of absorption spectroscopy, "steady state and time-resolved fluorescence" and fs transient absorption spectroscopy, and density functional theory (DFT) in order to assess the effect of decoupling the chromophores' low energy MOs on the rate of the singlet, S1, energy transfer, k ET , compared to a recently reported work on a heavily coupled trimeric system, Trimer 1, [biphenylenebis(n-nonyl)porphyrin zinc(II)]-bisarylporphyrin free-base ( A…
Transient absorption spectra and relaxation kinetics in Nb-doped PbWO4 scintillating crystals
2001
Abstract The spectra and relaxation kinetics of absorption induced by a pulsed electron beam were studied for undoped and Nb-doped PbWO 4 single crystals. A significant influence of Nb doping on transient absorption was found. The influence of Nb doping on the relaxation kinetics is proposed to be due to an oxygen vacancy involving electron–hole recombination. A delay was observed (35– 50 ns ) between the growth of F-centers and the irradiation pulse. A large portion of the F-centers decays within ∼16 μs due to recombination with mobile holes. The prolonged recombination processes are responsible for the decrease of the scintillation yield in PbWO 4 : Nb crystals.