Achieving accurate and effective modeling of the vehicle-to-vehicle (V2V) communication channel has proven to be a challenging task, particularly owing to the highly dynamic nature of vehicular ...environments. V2V channels generally may have contributions from the line-of-sight path, reflections from large stationary and moving objects such as bridges and other vehicles, and a diffuse base from large numbers of small stationary objects in the environment. We propose a new geometrical model for the diffuse component based on scattering objects distributed along the roadside, and use this model to predict the Doppler spectrum and angle-of-arrival distribution associated with this component for various V2V scenarios. In contrast with previous roadside scattering models that sum the contributions from large numbers of randomly-generated scattering objects, our model assumes a uniform linear distribution along the roadside. This permits a computationally efficient, closed-form model. Comparisons with on-road measurement data as well as the double ring model demonstrate the validity and effectiveness of the proposed model.
To extend the application of shooting and bouncing rays (SBR) method in the penetration structure and further improve the calculation accuracy, an improved mesh free SBR method that completely ...implements ray‐tracing and electromagnetic computing in 3‐D geometrical modeling software is proposed. The basic idea is to combine the non‐uniform rational b‐splines (NURBS) surface modeling function and open application programming interface (Open API) to implement the process of mesh free ray tracing, which greatly improve calculation accuracy and efficiency of SBR. Based on this, the improved SBR method can yield a superior performance for scattering analysis of complex targets, especially at the problem where reflected and transmitted waves exist simultaneously in a target. The numerical results demonstrate that the improved SBR is highly effective in computing scattering fields of complex targets.
A recent method for modeling folds uses a fold frame with coordinates based on the structural geology of folds: fold axis direction, fold axial surface and extension direction. The fold geometry can ...be characterised by rotating the fold frame by the pitch of the fold axis in the axial surface and the angle between the folded foliation and the axial surface. These rotation angles can be expressed as 1D functions of the fold frame coordinates. In this contribution we present methods for extracting and automatically modeling the fold geometries from structural data. The fold rotation angles used for characterising the fold geometry can be calculated locally from structural observations. The fold rotation angles incorporate the structural geology of the fold and allow for individual structural measurements to be viewed in the context of the folded structure. To filter out the effects of later folding the fold rotation angles are plotted against the coordinates of the fold frame. Using these plots the geometry of the folds can be interpolated directly from structural data where we use a combination of radial basis function and harmonic analysis to interpolate and extrapolate the fold geometry. This contribution addresses a major limitation in existing methods where the fold geometry was not constrained from structural data. We present two case studies: a proof of concept synthetic model of a non-cylindrical fold and an outcrop of an asymmetrical fold within the Lachlan Fold belt at Cape Conran, Victoria, Australia.
•Method for extracting fold geometry from structural data applicable to polydeformed terranes.•Geologically reasonable extrapolation of fold geometry using best fit Fourier series to structural data.•Integrated into existing fold modeling framework.•Application to asymmetrical folds from Cape Conran, Victoria, Australia.
Modeling tradition is reviewed within its historical maturity from Plato do Penrose. Metaphors in nonisothermal kinetics achieved a wide application mostly employing models derived by means of ...undemanding isothermal descriptions. Geometrical basis of such modeling is revised and discussed in terms of symmetrical and asymmetrical (pentagonal) schemes. The properties of interface (reaction separating line) are found decisive in all cases of heterogeneous kinetics. Application of fractal geometry is accredited, and associated formal kinetic models based on nonintegral power exponents are acknowledged. Typical erroneous beliefs are dealt with showing common kinetic misinterpretation of measured data and associated mathematical manipulability of kinetic equations. The correction of a measured DTA peak is mentioned assuming the effects of heat inertia and temperature gradients.
The rapid growth demanding for oil and gas resources has gradually driven the fossil energy exploitation from the land to the ocean. Technology shifts from manually operated oil fields to the ...remotely operated oil fields is necessary, and robotic assistance to human cognition is essential. Hot tapping and line stop techniques, as a great method for the replacement of the risky pipelines without disrupting the service to customers, demands for the automation to improve the efficiency and reliability. In this paper, automatically trajectory control of a spherical isolation plug in subsea pipeline was investigated. Mathematical model for the spherical plug head insertion was presented, and two control algorithms for the automatically insertion of the plug were proposed, named the rotation angle based control algorithm and the vertical displacement based control algorithm. Simulation was conducted and the results indicate that the vertical displacement based control algorithm owes better performance than the rotation angle based control algorithm. The accuracy and efficiency of the vertical displacement based control algorithm was then experimentally researched. The results in this paper can provide references for the automatically trajectory control of an isolation plug, as well as improve the accuracy and reliability of offshore hot tapping.
•Automatically trajectory control of a spherical isolation plug was investigated.•Two control algorithms for the control of the spherical plug head were proposed.•The performance of these two algorithms were compared and verified by experiments.
Fault slip rate variability over time is a crucial aspect for understanding how single faults interact among each other in fault systems. Several studies worldwide evidence the occurrence of high ...activity periods with clustering of events and synchronization among faults, followed by long periods of low activity (super-cycles). The increasing gathering of evidence of these phenomena is making fault hazard models quickly evolving and challenging seismic hazard assessment. However, in moderately active fault systems, a determination of fault slip rates can present large uncertainties, that have to be carefully considered when slip rate histories are determined. In this work, we estimate the variation of slip rate in the last ∼210 ky of the NE segment of the left-lateral reverse Carrascoy Fault, one of the main faults forming the Eastern Betic Shear Zone in SE Spain. We study two selected field sites where we have been able to measure offsets and date the sediments along with uncertainties. The first site shows a progressive discordance drawn by different calcretes developed on alluvial deposits. The vertical throw is calculated by modeling the growth of the discordance. The vertical slip rates are estimated dating the deformed calcretes by Uranium Series and by comparing them with a complete regional calcrete dates database compiled from the literature. On the second site, we analyze the geomorphology of different Upper Pleistocene alluvial fans, where three incised channels are offset by the fault, providing the net slip for the last ∼124 ky. We discuss the influence of different factors on the estimate of net slip rates using data from different sources. This analysis highlights the importance of determining an accurate fault geometry and how local data can provide misleading deformation rates. Our results suggest the existence of long periods of low activity disturbed by short high activity periods. Such a pattern of activity along time is defined for the first time in the Eastern Betic Shear Zone, with interesting implications in the seismogenic behavior of the rest of the slow faults within the region.
The recently introduced acoustic ray-tracing semiclassical (RTS) method is validated for a set of practically relevant boundary conditions. RTS is a frequency domain phased geometrical acoustics ...method which directly reproduces the acoustic Green's function. As previously demonstrated for a rectangular room and weakly absorbing boundaries with a real and frequency-independent impedance, RTS is capable of modeling also the lowest modes of such a room, which makes it a useful method for low-frequency sound field modeling in enclosures. In practice, rooms are bounded with diverse types of materials, resulting in a frequency-dependent, phase-modifying absorption/reflection. In a realistic setting, we test the RTS method with two additional boundary conditions: a local-reaction boundary simulating a resonating absorber and an extended-reaction boundary representing a porous layer backed by a rigid boundary described within the Delany-Bazley-Miki model, as well as a combination thereof. The RTS-modeled spatially dependent pressure response, frequency-band decay curves and reverberation times are compared to those obtained by the finite element method. The RTS results show systematic agreement for all boundary conditions and disclose some interesting particularities of the method.
In the current investigation, FeCoNi(MnSi)x (x=0.0,0.1,0.25,0.5,0.75,1.0) high entropy alloys (HEAs) were effectively processed by mechanical alloying (MA) route. The impact of Mn and Si on the ...FeCoNi system was further analyzed based on structural, morphological, and magnetic properties utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) at various processing stages. The results showed the formation of the Fe-rich BCC (major) + Ni-rich FCC (minor) phase in FeCoNi(MnSi)x (x=0.0,0.1,0.25) alloys however the Ni-rich FCC phase was significantly more recognizable in the case of FeCoNi(MnSi)x (x=0.5,0.75,1.0) HEAs. Furthermore, different symmetrical and asymmetrical geometrical thermodynamic models such as Muggianu, Lück chou, Kohler, Colinet, Hillert, Toop, and General solution model (GSM) were modeled using the Redlich-Kister formalism and then correlated the enthalpy value with the developed phases during MA. In the case of the GSM model, the enthalpy of mixing (ΔHmixGSM) was found to be negative in a whole concentration range of (MnSi)x at 1237 K and exhibited solid solution criteria confirmed from the enthalpy of mixing (ΔHmixMiedema) according to the Miedema model. Moreover, the associated activity coefficient (γa) revealed a negative deviation as Mn-Si content increased. Additionally, the magnetic properties showed a ferromagnetic nature, and its parameters were calculated from the "law of approach to saturation."
Display omitted
The geometry of discontinuities in a rock mass is one of the most important influences on the behavior and characteristics of that rock mass. The geometry of discontinuities largely determines the ...stability of the rock mass, as well as appropriate methods for reinforcing and stabilizing that mass. This study introduces the 3DDGM (three-dimensional discontinuity geometrical modeling) method, which is based on the 3DGM (three-dimensional geometrical modeling) algorithm that was developed using the Mathematica software package. The 3DDGM method provides essential input data for the stability analysis of a discontinuous rock mass using block stability assessment techniques or block modeling codes. The 3DDGM method developed in the present work was designed to model discontinuities in rock masses and to provide accurate values for discontinuity parameters (i.e., location, spacing, separation, system, orientation, etc.). This algorithm was developed to increase the accuracy of the discontinuity model based on the Heliot algorithm. The 3DDGM algorithm was tested by applying it to a real case, the sloping discontinuous rock mass at the phase 7 gas flare site in the South Pars Gas Complex in Assalouyeh, Iran, and the algorithm was successful in providing a three-dimensional model of the discontinuities in the rock mass at the site.
As soft elements for force transmission, braided fiber ropes play important roles in many fields where the fiber ropes are used bent over sheaves, while the relevant experiments are time-consuming ...and expensive. Computational simulation is a promising choice for evaluating the performance of fiber ropes when bent over a sheave. This article presents two methods that could be employed to build a model of braided rope bent over a sheave. One is the mathematical method which deduces the exact mathematical equations of braiding curves based on the Frenet–Serret frame. The spatial equations, considering the phase difference of strands in the same direction and the difference of strands’ projection in different directions, are discussed carefully. The final equation of braided strands is confirmed by modeling the braided rope in Maple® 17. The other method, which is inspired by the analysis of braiding movements, is based on the intersection of surfaces of braiding surface and helical surface which are introduced and defined based on the motion analysis of bobbins and take-up roller. The SolidWorks® 2018 is successfully employed to realize the modeling process.
PDF
