In this paper, a nonlinear continuum method is developed to predict the load-displacement response of single piles under lateral loading. This pseudo3D numerical procedure called the nonlinear vertical slices model (N...
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In this paper, a nonlinear continuum method is developed to predict the load-displacement response of single piles under lateral loading. This pseudo3D numerical procedure called the nonlinear vertical slices model (NVSM) consists of subdividing the pile/soil continuum into vertical interacting slices, each being dealt with as pseudo-plane stress problem. The technique takes advantage of finite element 2D numerical solutions in plane stress for building approximate 3D solutions. First, the linear FE VS model is briefly outlined and then the yield criterion selected for nonlinear analysis is introduced. The nonlinear computational strategy and the different calculation steps are also given in detail. Based on the theory of the NVSM, a computer code called Pile3D-NVSM for laterally loaded piles is presented. The computational advantage of the approach is illustrated, by the validation of the code through pile problems involving nonlinear soil behaviour. The reasonable agreement that has been found between the NVSM results and those of the full 3D FE method demonstrates the ability of the nonlinear vertical slices model to predict accurate lateral pile deflections.
Benznidazole (BZ) and nifurtimox are first-line drugs for the treatment of Chagas disease, with BZ preferred due to its moderate side effects compared to nifurtimox. However, BZ has low aqueous solubility and a low di...
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Benznidazole (BZ) and nifurtimox are first-line drugs for the treatment of Chagas disease, with BZ preferred due to its moderate side effects compared to nifurtimox. However, BZ has low aqueous solubility and a low dissolution rate which potentially limit its oral bioavailability. We now report for the first time efforts to improve the aqueous dissolution of BZ via processing and gamma-cyclodextrin (7-CD) complexation using supercritical carbon dioxide (scCO(2)). We first investigated the solubility of BZ in scCO(2 )and the effect of scCO(2) processing on the solid-state, particle size characteristics and dissolution behaviour of processed BZ compared to un-processed BZ. Moreover, the efficacy of scCO(2) in dissolving and complexing BZ with 7-CD was studied and compared with conventional freeze-drying (fd). The solubility of BZ in scCO(2) was time-dependent (1.78 x 10(-6) to 3.18 x 10(-)(5) mol. mol(-1)) and reached the equilibrium after 10 h. Complexation efficiency and loading capacity were in the range of 4 +/- 1.4% to 54 +/- 10% and 1.8 +/- 0.1% to 27 +/- 5%, respectively, and they varied depend on the preparation method and conditions. XRD, DSC, and FTIR results revealed that although scCO(2) was able to solubilise BZ, it did not change the solid-state morphology of BZ. Contrary, fd and gamma-CD complexation were shown to affect the solid-state characteristics of BZ and gamma-CD. The mean particle size of processed BZ was significantly reduced from 604 +/- 61.50 nm (un-processed BZ) to 257 +/- 41-385 +/- 36.56 nm (processed BZ). Both the dissolution rate profiles and dissolution efficiency differed depending on preparation methods, process conditions, and BZ-to-gamma-CD ratio, but they were significantly increased compared to un-processed BZ. Overall, this study demonstrated that the preparation methodology had substantial effects on the solid-state particle size/morphology characteristics and aqueous dissolution behaviour of BZ, both alone or in complexes with
By comparing the standard and staggered grid methods, a high-order rotated staggered grid algorithm has been developed for simulating seismic wave propagation in heterogeneous viscoelastic or transverse isotropic medi...
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By comparing the standard and staggered grid methods, a high-order rotated staggered grid algorithm has been developed for simulating seismic wave propagation in heterogeneous viscoelastic or transverse isotropic media. Numerical simulation results show that, staggered high-order staggered fd method is better than staggered pseudo-spectral method in modelling heterogeneous anisotropic or viscolastic media. Based on the algorithm, a uniform random function is used to establish random models with two kinds of components, i. e., clays and pure sandstones. These two media consist of various synthetic shale sand formations and are simulated for various clay contents. Elastic wave velocities and attenuations for various clay contents are simulated properly at the frequency around 10 kHz to 100 kHz. The numerical results show that our developed algorithms can be used for modelling composite media for studying elastic wave attenuation and velocity variation. The modelling analyses demonstrate that, the more the clay particles in the models, the more reflected backscattering produced when the wave length is around equal to the 10 times of the minimum size of the clays.
A sequential waveform method is developed to simulate the seismic response of basin-edge structure excited by a plane incident *** full procedure involves:(a) a previous parameterization of the investigated model usin...
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A sequential waveform method is developed to simulate the seismic response of basin-edge structure excited by a plane incident *** full procedure involves:(a) a previous parameterization of the investigated model using the seismic wave velocities and depths of the sedimentary stratifications;(b) an input motion determined from the records at stations installed on hard rock;(c) forward computation of the P-SV elastic wave field by means of a two-dimensional finite difference(fd) method;(d) the optimization of the model vector using simulated annealing technique and comparing the simulated seismic response of the tested structure with the observed wave field;(e) the correction of the initial model by trial-and-error by testing the differences between synthetics and observed data,and(f) the final solution obtained by iteration using the conjugate gradient *** search of an optimal basin-edge model has been parallel processed by varying the shapes and velocities of strata on the basis of the fitting of relative timing,amplitude and phase between the output and the observed *** input motion and sensitivity have been checked and the validity of the method has been demonstrated by numeric *** the teleseismic records generated by 7 earthquakes recorded at 26 broadband seismic stations,we have studied the seismic velocity structure of the southern edge of the Jiyang depression located in the Bohai Bay basin,northern *** cross sections show an agreement between the velocity results and the geological sections available in the *** addition,we obtain evidence of three hidden faults under the sections and features that suggest major extensions at the Paleogene.
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