Cone angle influence on dynamic light cone penetrability and its effect on tip resistance prediction

The recent technological developments made on the light dynamic penetration test Panda 3 R provide a dynamic load–penetration curve σ p − s p for each impact. This curve is influenced by the mechanical and physical properties of the investigated granular media. In order to analyze and exploit the load-penetration curve, a numerical model of penetration test using 3D Discrete Element Method is proposed for reproducing tests in dynamic conditions in granular media. All parameters of impact used in this model have at first been calibrated by respecting mechanical and geometrical properties of the hammer and the rod. There is a good agreement between experimental results and the ones obtained from simulations in 2D or 3D. After creating a sample, we will simulate the Panda 3 R. It is possible to measure directly the dynamic load–penetration curve occurring at the tip for each impact. Using the force and acceleration measured in the top part of the rod, it is possible to separate the incident and reflected waves and then calculate the tip's load-penetration curve. The load–penetration curve obtained is qualitatively similar with that obtained by experimental tests. In addition, the frequency analysis of the measured signals present also a good compliance with that measured in reality when the tip resistance is qualitatively similar.

The paper presents a numerical study on the influence of the properties of granular media on light dynamic penetration test results. A numerical model based on the Discrete Element Method (DEM) in 2 dimensions has been carried out. The model is able to reproduce the penetration tests in dynamic conditions. The model provide for each impact, the load–penetration curve that presents the evolution of reaction forces of granular media acting on the tip of the penetration test. The load – penetration curves are investigated in terms of tip resistance and analyzed by using the Discrete Fourier Transform in order to study the oscillations of the curves. The influence of the properties of granular media on the load-penetration curve has been investigated. We concentrated on the influence of particle friction and sample compacity. Besides the known results obtained in the literature by the dynamic tip resistance analysis for macroscopic response, we found that for a particle friction greater than 0.5, tip resistance and oscillations of signal are stable. Concerning the sample compacity, although variation of volume fraction is tight (ϕ = 0.817 − 0.844), a clear variation in terms of tip resistance and amplitude spectrum is highlighted.

Geotechnical investigation is a crucial exercise in availing ground characteristics for safer and economical design and construction of infrastructures. In-situ testing for geotechnical investigation: such as Cone Penetration Test, when adopted to supplement field sampling and Laboratory tests offers economic benefit in terms of time saving and reduced cost for investigation. It is proven that dynamic cone testing offers additional benefits over static cone testing. Intensive research conducted for static cone testing has enhanced its accuracy for ground characterization. There are observed potential benefits of Light cone dynamic testing for shallow depth investigations (to 10 m depth). This review paper is aimed at exploring the information available on equipment specifications, standardization, application and interpretation models/monographs. The review has presented the gaps available in order to enhance predictability power of dynamic light cone penetration test. Furthermore, the review directs the focus on research in advancing the predictability power of the test. Dynamic Light Cone Testing; Dynamic Cone Tests; Static cone Testing; Standard Cone Penetration Test; Correlation

1. Deposits of hydraulic-filled silty tailings are characterized by a loose structure, light cone penetration resistance, and rather high strength indices (cohesion). 2. There is a close relation, represented by Eqs. (1), (2), and (3) between the results of dynamic sounding and the characteristics of tailings. 3. The cone penetration resistance of tailings increases considerably with time, mainly due to an increase in strength of the fill material. The gain in strength of the tailings with time can be explained by strengthening of the crystallization bonds and further cementation by salts precipitating from solutions of the liquid phase of the tailings percolating through the filled deposits.

Preloading coupled with vertical drains is a successful ground improvement technique for soft clay deposits. Though surcharge in the form of sand pile is conventionally used, vacuum consolidation is also an option. This paper presents a case study on ground improvement using vacuum consolidation technique carried out near the shoreline in the city of Kakinada, Andhra Pradesh. Detailed methodology, method of installation of PVD, settlements observed during the consolidation process and results from light cone penetration test performed to quantify the ground improvement and the insights gained from the study are described.

Light from a small aperture at the focal plane of a collimator appears as a point source located at infinity. Light from the aperture of a blackbody is imaged onto the small focal plane aperture. This defines the input cone of light. The light exiting from the focal plane aperture into the light cone collected by the collimator is calculated in this article using a diffraction model. The input cone angle is shown to be the only system parameter affecting the spectral transmission of a given aperture. Data from the POST test chamber is presented to demonstrate the model. The data is analyzed at longwavelength (LWL) and at shortwavelength (SWL) to yield a measured value of the input cone angle. The SWL data, diffraction losses less than 20%, and the LWL data, diffraction losses from 20 to 60%, give nearly identical values for the cone angle. The measured cone angle is near to the design value of the cone angle.

Topological insulators exhibit an axion-mediated magnetoelectric response that generates cross-polarised scattering channels strictly forbidden in conventional dielectrics, an optical fingerprint of the topological surface states themselves. Exploiting this fingerprint experimentally requires structured illumination capable of selectively amplifying the cross-polarised channel while suppressing background Mie scattering. Here we show that non-diffracting Lommel beams fulfil this role in a way that symmetric Bessel beams fundamentally cannot. We present the first theoretical treatment of polarised Lommel beam scattering by a topological insulator sphere, extending generalised Lorenz-Mie theory to incorporate the full topological magnetoelectric boundary conditions and deriving closed-form cross-polarised scattering coefficients as a function of the axion angle θ0. The central result is that the Lommel asymmetry parameter c provides continuous, tunable control over multipole excitation: by varying c, one preferentially drives the multipole orders that couple most strongly to the axion term, amplifying the cross-polarised signal while suppressing the co-polarized background, a capability absent in any cylindrically symmetric beam. At moderate axion coupling (θ0 = π), the cross-polarised-to-co-polarized intensity ratio reaches order 10⁻², well within the detection range of standard polarimetric instrumentation. The inversion protocol for recovering the axion angle shows that the phenomenon is no longer a computational study of a beam-material combination; instead, it is a non-contact optical metrology protocol for axion angle retrieval. The ratio of cross-polarised to co-polarised scattering intensity increases nonlinearly and monotonically with θ0, confirming an unambiguous optical signature of the topological magnetoelectric effect. Circularly polarised Lommel beams further reveal pronounced handedness-dependent scattering asymmetry arising from spin-orbit coupling at the surface states. These results establish a quantitative framework connecting structured light parameters, topological charge, asymmetry, cone angle, and polarisation, to axion electrodynamics, and identify spatial-light-modulator-generated Lommel illumination as a practical, non-contact route to optical characterisation of topological surface states in Bi₂Se₃ and Bi₂Te₃ nanoparticles.

In order to improve the light extraction for the deep ultraviolet light emitting diodes (DUV-LEDs), the surface microstructure based on a parabola cone array is used and optimized in work. In the optimization of the surface structure, inverse design based on a particle swarm optimization intelligent algorithm is applied to maximize the light extraction. The optimization results show that compared with the traditional planar structure, the optimized surface structure improves the light extraction efficiency by more than 200%. In addition, the influence of the designed surface microstructure on the light propagation is also explored by comparing the light field distribution and the light extraction process with the planar structure DUV-LEDs. It is revealed that the high aspect ratio of an array microstructure can change the light propagation and greatly expand the angle of a light escape cone. This effect can be maximized by the inverse design based on the intelligent algorithm, which has great potential in improving the light extraction of AlGaN-based DUV-LEDs.

For the design of shallowly embedded small size pile under lateral load, a new kind of electronic miniature cone penetrometer is developed. And a novel mini calibration chamber is also designed to form homogeneous soil specimens for miniature cone penetration test (MCPT) in laboratory. A series of MCPTs and pile loading tests in silty clay are carried out. For silty clay, penetration curve has no correlation with cone angles within the tested range of 19° to 32°. The initial segment of penetration curve is linear for silty clay. However, the cone tip resistance tends to be stable when the cone is penetrated to a certain depth. It is implied that the critical depth effect occurs for MCPT of silty clay. For silty clay, the critical depth effect is caused by different soil failure mechanisms under different confining pressures. The lateral bearing capacity and stiffness of small size pile are all directly related to the ultimate cone tip resistance of soil. It is concluded that the miniature cone penetrometer is an effective apparatus for the design of small size shallowly embedded pile.

Finite element cavity expansion analysis investigating the effect of penetration rate on piezocone tests in clay is presented. A coupled analysis was performed, in which the rate of cavity expansion was linked to the penetration rate of the cone and the cone angle, using the assumption that the deformation was wholly radial, and took place only between the cone tip and the cone shoulder. The soil was modelled using modified cam clay with two sets of parameters and varying values of overconsolidation ratio (OCR). The influence of penetration rate on the stress and pore pressure distributions was examined. For slower penetration rates, the excess pore pressure at the cone shoulder is lower since consolidation is permitted coincident with penetration. The radial profiles of post-penetration voids ratio demonstrate that partially drained penetration is permitted by volume change in the near field, in addition to radial movement in the far field. The radial distribution of excess pore pressure after slow penetration differs from the undrained case, with a relatively low radial gradient existing at the cone face. As a result, the dissipation curves after slow penetration lag behind those following fast penetration. The cone velocity is made dimensionless by normalizing with the coefficient of consolidation and the cone diameter. ‘Backbone’ curves of normalized velocity against normalized tip resistance and excess pore pressure capturing the transition from undrained to drained penetration are derived. The normalized pore pressure backbone curve is unique, whilst the normalized tip resistance shows a small dependency on OCR. These backbone penetration curves are compared with centrifuge model piezocone tests conducted at varying rates, and subsequent dissipation tests. The numerical and experimental results suggest that the value of consolidation coefficient operative during the dissipation phase is 2–4 times higher than the virgin compression value due to changes in the operative soil stiffness, as demonstrated from the stress paths of individual soil elements. The use of multi-rate penetration tests to deduce values of consolidation coefficient is discussed, in light of these differences. Copyright © 2005 John Wiley & Sons, Ltd.

A new kind of electronic miniature cone penetrometer is developed for miniature cone penetration test (MCPT), with which the cone penetration resistance and penetration depth can be acquired automatically. In order to form homogeneous soil specimens for MCPT, a new experimental facility is designed. A series of MCPTs in silty soil are carried out and it is found that, for silty soil, the curves of the penetration resistance vs. the depth have no correlation with the cone angles. For MCPTs in silty clay, the initial segment of the penetration curve is straight and the cone tip resistance tends to be stable when the cone is intruded into a certain depth, i.e. the critical depth. For silty clay, the critical depth effect of the cone tip resistance is related with the different failure mechanism of soil under different confining pressure. The relation between the characteristic values of the penetration curve and soil strength parameters is analyzed. The cone resistance factor is linear with the tangent of the internal friction angle of soil. The ultimate cone penetration resistance is found to be closely related to the critical depth.

All-dielectric film narrow band filter is widely used in laser system owing to its excellent optical capability, manufacturability and environmental adaptability. But 905nm infrared semiconductor laser system have large divergence angel so we designed entrance light cone angle 905nm narrow band filter. And center wavelength shift, due to entrance light cone angle, affects its spectral selective power seriously. In order to reduce these impacts, an informal dielectric film narrowband filter is designed. Changes of transmission characteristics with oblique incidence of Gaussian beam of uneven illumination are analyzed. The relationship between the angle of incidence and the central wavelength shift quantificational are Solved. A ± 30 ° incident 905nm narrowband filter was fabricated. Between 880nm and 950nm, the average transmittance is above 90%, and at the cut-off band the average transmittance is below 1%.

Wavien patented dual paraboloid reflector (DPR) system, while optimal in maximizing image brightness (equivalent to minimizing the image aberration) at the input of its light pipe, does not produce maximal lumen throughput at its output. The overall lumen throughput depends in large part on three factors: Fresnel losses and image aberration, both defined at the input face of the light pipe, and the light pipe's input dimensions. Fresnel losses can be reduced by narrowing the cone angles of the light cone incident on the light pipe, which in turn can be achieved by increasing the size and/or focal length of the second paraboloid reflector. Smaller cone angles also mean reduced tapering of the light pipe which translates into larger input sizes (as its output dimensions are fixed) and higher coupling efficiency. Unfortunately this gain in coupling efficiency comes at the expense of breaking the system symmetry, which destroys 1:1 imaging and leads to increased aberration and reduced brightness. Using a ray-tracing software an optimal point of operation can be reached and it is found that at least 10% increase in lumen throughput over the symmetric DPR system is achievable.

The paper deals with the homogenization of a magneto-elastodynamics equation satisfied by the displacement \(u_\varepsilon \) of an elastic body which is subjected to an oscillating magnetic field \(B_\varepsilon \) generating the Lorentz force \(\partial _t u_\varepsilon \times B_\varepsilon \). When the magnetic field \(B_\varepsilon \) only depends on time or on space, the oscillations of \(B_\varepsilon \) induce an increase of mass in the homogenized equation. More generally, when the magnetic field is time-space dependent through a uniformly bounded component \(G_\varepsilon (t,x)\) of \(B_\varepsilon \), besides the increase of mass the homogenized equation involves the more intricate limit g of \(\partial _t u_\varepsilon \times G_\varepsilon \) which turns out to be decomposed in two terms. The first term of g can be regarded as a nonlocal Lorentz force the range of which is limited to a light cone at each point (t, x). The cone angle is determined by the maximal velocity defined as the square root of the ratio between the elasticity tensor spectral radius and the body mass. Otherwise, the second term of g is locally controlled in \(L^2\)-norm by the compactness default measure of the oscillating initial energy.

All-dielectric film narrowband filter is widely used in space-borne multispectral remote sensor owing to its excellent optical capability, manufacturability and environmental adaptability. But center wavelength shift, due to entrance light cone angle, affects its spectral selective power seriously. In order to study effects of incident light cone on transmission characteristics of narrowband filter, an informal dielectric film narrowband filter is designed and manufactured. Changes of transmission characteristics with oblique incidence of Gaussian beam of uneven illumination are analyzed. The count model of effective transmission with vertical incidence light cone is established and verified by spectral calibration. Results show that blue shift of central wavelength is the main influence of incidence light cone on transmission characteristics of all-dielectric film narrowband filter. Prediction accuracy of transmittance calculated by effective transmission model is better than 0.15% of central wavelength. Therefor, count model of effective transmission can be used to calculate the actual transmittance of film narrowband filter with oblique incidence of Gaussian beam, and spectral selective ability of narrowband filter will be improved when the reasonable film design data corrected by center wavelength shift is utilized during film coating. This provides a new technical approach to solve the problem of the wavelength shift of film narrowband filter with vertical incidence light cone.