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How to determine the unusual stratum load for metro tunnel under the influence of ground fissure is a major challenge faced by the construction of Xi'an Metro in China. In this paper, based on the theories of Bierbaumer and Terzaghi, a limit equilibrium form of stratum holding effect principle is proposed as an alternative solution for calculating the unusual stratum load experienced by metro tunnels crossing ground fissures at different intersection angles. Our methodology uses the movement mode of stratum-tunnel induced by active ground fissure to construct the analysis model, while considering soil properties and strength, holding force, tunnel buried depth, segment diameter, and the intersection angle between tunnel and ground fissure. Fundamental formulae for the development of soil fracture angle during this movement process are also derived and analyzed. The methodology is also illustrated and validated by two representative examples, and the sensitivity of parameters affecting the results is discussed as well, providing some design suggestions for practical engineering. The presented alternative way of calculating the unusual stratum load in the active ground fissure site might be helpful for the design of metro engineering to meet the necessary degree of safety.

How to determine the unusual stratum load for metro tunnel under the influence of ground fissure is a major challenge faced by the construction of Xi'an Metro in China. In this paper, based on the theories of Bierbaumer and Terzaghi, a limit equilibrium form of stratum holding effect principle is proposed as an alternative solution for calculating the unusual stratum load experienced by metro tunnels crossing ground fissures at different intersection angles. Our methodology uses the movement mode of stratum-tunnel induced by active ground fissure to construct the analysis model, while considering soil properties and strength, holding force, tunnel buried depth, segment diameter, and the intersection angle between tunnel and ground fissure. Fundamental formulae for the development of soil fracture angle during this movement process are also derived and analyzed. The methodology is also illustrated and validated by two representative examples, and the sensitivity of parameters affecting the results is discussed as well, providing some design suggestions for practical engineering. The presented alternative way of calculating the unusual stratum load in the active ground fissure site might be helpful for the design of metro engineering to meet the necessary degree of safety. [ABSTRACT FROM AUTHOR]

Conjugate electrospinning, with two oppositely placed and charged spinning nozzles, is a modified electrospinning technique to prepare continuous nanofibers with the aligned structure. In the present work, conjugate electrospinning is used to prepare highly aligned polyvinyl pyrrolidone (PVP) nanofibers. The influences of an unheeded parameter, the intersection angle between the oppositely charged spinning nozzles, on the morphology and alignment of the polymer nanofibers are investigated. It is found that the alignment degree of the nanofibers increases first and decreases then when the intersection angle increases from 60 to 240°, reaching the best alignment at the angle of 120°. The main reason is that the swing fibers on the same side entangle together when the intersection angles are small, and those mutually attracted ones from the opposite side also entangle at high intersection angles. Raising the collecting rate can improve the alignment degree of the PVP nanofibers. The critical collecting rate (beyond which the collecting fibers will fracture) increases at higher intersection angle. Though the fibers prepared at 240° are collected at a higher rate, their alignment degree is still worse that of the fibers spun at 120°. In summary, to acquire well-aligned nanofibers by conjugate electrospinning, an appropriate intersection angle between the oppositely charged spinning nozzles should not be neglected. [ABSTRACT FROM AUTHOR]

The application field of global navigation satellite systems continues to expand, and their security and stability have received widespread attention. Navigation spoofing has the characteristics of solid concealment and significant harm, posing a severe security threat to navigation systems. In current spoofing detection methods based on signal spatial correlation, multiple antennas/receivers or moving single antennas are required, which means high cost and complexity in implementation. To this end, we propose a spoofing detection method based on the intersection angle between two directions of arrival (IA-DOA) for single-antenna receivers. The essence of this method is to accurately estimate the IA-DOA between a pair of signals based on pseudorange observations and navigation information. The observation should be consistent with the prediction when there is no spoofing. Otherwise, due to geometric and kinematic differences between the navigation satellite and the spoofer or the pulling off of the spoofing, the spoofing may disrupt the consistency between the observation and prediction of IA-DOA. Theoretically, since the proposed method makes no assumptions about spoofing, it can detect multi-antenna spoofing. We conducted a Monte Carlo simulation to analyze the impact of different parameters on spoofing detection performance and conducted experimental verification and evaluation through open datasets. The results show that the method proposed in this article can effectively detect multi-antenna spoofing, reducing the requirements of receiver antennas for spoofing detection methods based on signal spatial correlation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous brain studies have mostly focused on adults and fetuses, and the developmental characteristics of young children's brainstems have rarely been studied. OBJECTIVE: To observe the brainstem development characteristics of healthy young children and to explore the age-related differences and their correlation with sex. METHODS: From January 2019 to April 2022, a retrospective study of 3.0T MRI images of 174 children aged 2 to 6 years in the Affiliated Hospital of Inner Mongolia Medical University was conducted, and the median sagittal diameter, area and angle of the brainstem (including midbrain, pons and medulla oblongata) were measured. RESULTS AND CONCLUSION: There is an age-related increase in the anterior and posterior diameters of the midbrain, pons and medulla oblongata in the 2-5 years old group as well as in the longitudinal diameter and area of the midbrain, pons and medulla oblongata in the 2-6 years old group. Except for the longitudinal diameter of the medulla oblongata, all others show a positive correlation with age (r > 0, P < 0.05). In the 2-3 years old group and 4-5 years old group, the children are in the rapid growth and development stage, and these two age groups can be used as the key observation indicators for the development of young children. The anterior-posterior diameter, longitudinal diameter, area of the pons and total brainstem area are strongly correlated with age, which can be used as the key observation indicators for the brainstem development in young children. [ABSTRACT FROM AUTHOR]

The behavior of an existing shield tunnel is significantly affected by undercrossing shield tunneling. In previous theoretical analyses, however, the effect of the interaction angle between the new and existing shield tunnels on the settlement of the existing tunnel is missing. Furthermore, in conventional methods of calculating tunnel settlement, mechanical parameters of soils, such as the shear modulus of shear layer gs and the coefficient of subgrade modulus k, are mainly determined by engineers' experience, which may lead to subjective or even biased calculation results. This paper proposes an analytical method to predict the settlement of an existing tunnel subjected to the undercrossing excavation of a new tunnel with different intersection angles. The method implements an iterative process to find reliable foundation parameters and the dimensionless parameter γ (iteration factor) in the modified Vlasov model. The robustness of the proposed method is validated by comparing the calculation results with the field measurement of two practical projects, and good agreements are obtained. The influences of the intersecting angle, the clearance distance, and the ground volume loss on the settlement and bending moment of the existing tunnel are discussed in detail. Results indicate that the intersection angle of the new and existing tunnels plays a significant role in settlement of the existing tunnel. The proposed analytical method enables engineers to predict the settlement of the existing tunnel subjected to undercrossing tunneling with different interaction angles. [ABSTRACT FROM AUTHOR]

Spoofing against the Global Navigation Satellite System (GNSS) is an attack with strong concealment, posing a significant threat to the security of the GNSS. Many strategies have been developed to prevent such attacks, but current detection methods based on signal direction for multi-agent spoofing require multiple antennas/receivers, leading to increased cost and complexity in implementation. Additionally, methods utilizing a moving single antenna cannot effectively detect multi-agent spoofing. Therefore, we introduce a novel spoofing-detection technique based on the intersection angle between two directions of arrival (IA-DOA) using a single rotating antenna. The essence of this approach lies in estimating the IA-DOA between a pair of signals by utilizing the carrier-to-noise ratio (CNR) and carrier phase single difference (CPSD) of the received signal. The estimation of IA-DOA should be consistent with the prediction when there is no spoofing. With spoofing, it is difficult to accurately simulate the directionality of navigation signals, which can disrupt the consistency between the estimation and prediction of IA-DOA. Therefore, estimations and predictions of IA-DOA can be used to establish detection variables through generalized likelihood ratio testing (GLRT) to detect multi-agent spoofing. We conducted a simulation to analyze the impact of the antenna's parameters on the detection performance and evaluated it through on-site experiments. The results indicate that the method proposed in this article can efficiently achieve real-time detection of multi-agent spoofing. [ABSTRACT FROM AUTHOR]

Regarding the cross fracture structure of “卜” type as the basic unit of the fracture network to discuss the fracture network conductivity. The conductivity of shale slabs with the intersection angles of primary and secondary fracture of 30°, 60°, 90°, 120° and 150° were carried out, using a rubber sleeve with the outer circle and the inner square configuration as fracture conductivity chamber. And the fracture volume equivalent theory was used to calculate the network conductivity. The experimental results show that the secondary fracture contribute a lot to improve the fracture network conductivity regardless of the intersection angles of primary and secondary fracture and the concentration of proppant placement in the secondary fracture. And increasing the proppant placement concentration is beneficial to maintain in the fracture network conductivity stable and efficient under high closure stress. However, the larger the fluid confluence angle is, the greater the fluid energy loss caused by the fluid collision and other effects, which shows that the “卜” type fracture network conductivity decreases with the increasing the intersection angles of primary and secondary fracture. Therefore, fully considering the intersection angle of the fluid confluence has a significantly important role in accurately evaluating the fracture network conductivity. [ABSTRACT FROM AUTHOR]

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Given the increasing number of spoofing attacks, keeping global navigation satellite system transmissions secure has recently become a focus. Many approaches have been proposed to defend against spoofing. Typical antispoofing methods against a multiagent spoofer usually use the direction of arrival (DOA) with an antenna array to detect spoofing. However, not only the process of calibration but also the information on the attitude and position of the antenna array platform is required in advance, which means high cost and complexity in terms of implementation. To this end, we propose an antispoofing method based on the intersection angle between two directions of arrival (IA-DOA) for a multiantenna receiver. This angle metric is presented here for the first time. Once spoofing exists, the IA-DOA may not be satisfied with the specific constraint. In addition, the IA-DOA is demonstrated to be insensitive to the attitude of the platform. It is shown that the proposed method can significantly relax the requirements of antispoofing. The method can address spoofing detection and make it possible for spoofing classification. Furthermore, a generalized likelihood ratio test and a simplified detector are developed in the case of a quadruple-antenna configuration with a particular geometry and noise covariance. Finally, the statistical characteristics are analyzed theoretically through Monte Carlo simulations, and field experiments verify the detection performance. [ABSTRACT FROM AUTHOR]

The present study proposes a closed-form analytical solution for investigating the behaviour of buried adjacent pipeline subjected to ground heave induced from static pipe bursting underneath. The governing differential equation of the adjacent pipe is derived based on the concept of a beam (both Euler–Bernoulli's and Timoshenko's beam) resting on a Pasternak foundation. A Fourier series is used to solve the governing differential equation. The proposed solution is validated with the results obtained from earlier full-scale experimental works and finite-element-based numerical study. Further, a parametric study is conducted to investigate the influence of relative pipe–soil stiffness and pipe–pipe intersection angles on the adjacent pipe response during the pipe bursting process. It is perceived that normalised maximum pipe deformation reduces and normalised maximum pipe bending moment increases as the value of the relative pipe–soil stiffness increases. Further, for the present case, the maximum pipe curvature is obtained at a 35° intersection angle. Hence, it is understood that a 90° intersection angle is not always the critical criterion. The study will be useful in the preliminary design stage for obtaining quick and relevant results without performing rigorous numerical or experimental study. [ABSTRACT FROM AUTHOR]

The interaction of supercavitating strikers with obstacles placed in water was investigated in a wide range of intersection angles. Several options of the interaction of strikers with obstacles are considered, including through puncturing, destruction of the striker, and ricochet. Estimation was made of the magnitude of the decrease in the speed of strikers in the cases of through puncturing and ricochet. [ABSTRACT FROM AUTHOR]

In this paper, we studied the effects of the intersection angle between the inlet channels on the droplet diameter using a COMSOL Multiphysics® simulation. We employed the level-set method to study the droplet generation process inside a microfluidic flow device. A flow-focusing geometry was integrated into a microfluidics device and used to study droplet formation in liquid–liquid systems. Droplets formed by this flow-focusing technique are typically smaller than the upstream capillary tube and vary in size with the flow rates. Different intersection angles were modeled with a fixed width of continuous and dispersed channels, orifices, and expansion channels. Numerical simulations were performed using the incompressible Navier–Stokes equations for single-phase flow in various flow-focusing geometries. As a result of modeling, when the dispersed flow rate and the continuous flow rate were increased, the flow of the continuous flow fluid interfered with the flow of the dispersed flow fluid, which resulted in a decrease in the droplet diameter. Variations in the droplet diameter can be used to change the intersection angle and fluid flow rate. In addition, it was predicted that the smallest diameter droplet would be generated when the intersection angle was 90°. [ABSTRACT FROM AUTHOR]

Estimating the collision frequency of ships (F) is important for assessing collision risk on waterways. To date, F has been estimated as the product of the number of collision candidates $({N_{a }})$ and the causation probability $({P_c})$ : $F = {N_{a}} \cdot {P_c}$ , where ${N_{a }}$ represents the number of collisions that occur when related ships continue on course with no intervention, and ${P_c}$ is the probability that collision avoidance fails. Fujii developed a general method and Pedersen formulated it to estimate ${N_{a }}$ in an intersectional area. Their method is generally called 'the geometric method' because collision candidates are estimated only from the geometric relationship between two ships. The method has been used in many projects to estimate F in waterways; however, its use should be limited to intersection angles ranging from 10° to 170°. This paper presents a method, statistically verified by computer simulation, that can be used at all intersection angles to overcome this limitation. Moreover, it demonstrates strong agreement with Pedersen's method at intersection angles of 10° to 170°. [ABSTRACT FROM AUTHOR]

• The mechanical response and deformation characteristics of shield tunnels crossing ground fissures with different intersection angles are analyzed. • The failure mechanism of the segment lining and bolts of shield tunnels under the influence of ground fissures is revealed. • The influence of different intersection angles on the structural failure mode and the influence range of shield tunnels is determined. • The state changes of shield tunnels induced by ground fissure activity and corresponding countermeasures are discussed. Ground fissures are a typical slowly changing geological hazard that poses great safety risks to metro shield tunnels crossing ground fissures. To thoroughly analyze the deformation and failure of shield tunnels under the action of ground fissures with different intersection angles, this study reviews the existing research and carries out model tests on metro shield tunnels crossing ground fissures considering different intersection angles. Based on the experimental results and numerical simulations under multiple conditions, the deformation and failure characteristics of shield tunnels are systematically analyzed for the first time, which confirms that the activity of ground fissures can lead to a series of problems, including segment dislocation, lining cracking, structural elliptical deformation, bolt yield, joint opening and closing, void areas at the tunnel bottom in the hanging wall and tunnel top in the footwall, as well as resulting waterproof failure and internal gauge changes. In addition, as the intersection angle between tunnel and ground fissure increases, the failure mode of the structure gradually transitions from torsional failure to shear failure, with a decrease in the number of segment rings under bias pressure and an increase in the number of segment rings under shear effect. Based on the deformation characteristics, failure positions, and the changes of structural state of shield tunnels, some reflections on countermeasures are discussed, which can provide guidance for the design and maintenance of metro projects in ground fissure sites. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research has found a novel computationally efficient method of modelling flow at low Reynolds number through fracture networks. The numerical analysis was performed by connecting Hele-Shaw cells to investigate the effect of intersections on the pressure field and hydraulic resistance for given inlet and outlet pressure values. In this analysis, the impact of intersecting length, intersecting angle and fracture aperture on the fluid flow was studied. For this purpose, two models with different topologies were established. The Hele-Shaw simulation results for hydraulic resistance, pressure and velocity agreed well with results obtained by solving the full Navier–Stokes equations (NSE). The results indicated an approximately linear relationship between intersection length and hydraulic resistance. Specifically, an increase in the intersection length increases the flow rate and as a result, the pressure along the intersection length decreases. The error associated with employing the Hele-Shaw approximation in comparison with NSE is less than 2%. All investigations were performed in the Reynolds Number range of 1–10. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization process, more and more urban subway construction, inevitably space intersection of subway tunnels has been formed. Based on practical engineering cases, a three-dimensional model is established by using MIDAS-GTS/NX numerical software. The dynamic response of metro tunnel under seismic wave is analyzed. The effect of tunnel intersection angle on the dynamic response law is discussed. The results show that: (1) Acceleration amplification factor, internal force and displacement of intersecting tunnels increase first and then decrease along the measuring points. The dynamic response of the area where the upper and lower tunnels intersect is the strongest. (2) The dynamic response of the tunnel in the upper soil is stronger than that in the lower rock. The difference of dynamic response between two tunnels in the same stratum is small. (3) With the increase of the intersection angle between the upper and lower tunnels, the acceleration and shear force decrease gradually. There is a negative correlation. The exponential function is established to describe the functional relationship between the dynamic response and the angle. The research results can provide references for earthquake resistance and shock absorption of urban metro. [ABSTRACT FROM AUTHOR]

The effect of intersection angle on the primary and secondary atomization of vacuum induction melting gas atomization (VIGA) was studied by the combination of experiments and computational fluid dynamics CFD simulations. The VOF (volume of fluid) multiphase flow model based on the Euler-Lagrange method was used to simulate the primary atomization process and the discrete phase model (DPM) was used to simulate the breakup process and predict the particle size distribution (PSD) of Taylor analogy breakup (TAB) in secondary atomization. The results show that the simulated area of recirculation zone decreases with the increase of intersection angle. The fragmentation morphology of metal melt is presented as "fountain→umbrella" and the primary droplets size is 0.3~0.9mm. The Weber number (We) of liquid droplets is 10~90. With increasing intersection angle， the average particle size of the powders decreases gradually. Moreover， these simulation results prove reasonable， which the simulated particle size of the powders is in agreement with the experimental one when the intersection angle is 36°. [ABSTRACT FROM AUTHOR]

A real 3D model is developed to study the interaction between hydraulic fracture and natural fracture. The hydraulic fracture propagation behavior and fracture geometry under impact of natural fracture are studied through a series of numerical results, different horizontal stress anisotropies, intersection angles, friction coefficients as well as hydraulic parameters. The final results demonstrate the key role of horizontal stress anisotropy on the interaction between hydraulic fracture and natural fracture. Under a higher intersection angle, it is difficult for hydraulic fracture to cross the natural fracture with low horizontal stress anisotropy. In addition, the natural fracture at a lower intersection angle has a higher probability to capture the hydraulic fracture. Normally, the natural fracture is more likely to be activated in the top branch at a low intersection angle, as the lower branch is located in the induced stress shadow of hydraulic fracture. By contrast, two different branches,+ especially two symmetrical braches at the intersection of 90°, are activated. On the other hand, a higher friction coefficient slows down the propagation in natural fracture, even prevents the activation of natural fracture. Besides, increased injection rate as well as fluid viscosity will promote the fracture propagation under the same conditions to lead to a longer and wider fracture. [ABSTRACT FROM AUTHOR]

Abstract Accurately predicting the propagation of hydraulic fracturing arising from the wellbore is essential in petroleum engineering, hydraulic engineering, etc. There are various factors influencing fracture propagation, such as the initial fracture orientation and in-situ stresses, while the limitation of appropriate methods and techniques hinders the further investigation on the propagating mechanism. In the study, a simulator based on High-order Generalized Finite Element Method (GFEM) is introduced to investigate the propagation behaviors of hydraulic fractures arising from the sidewall of wellbore. For better recognization of hydraulic fracturing, several numerical examples are performed based on the simulator. Different influencing factors are studied, including intersection angle between fracture and wellbore, in-situ stresses and fracture interactions. It is found that, regardless of in-situ stresses in the surrounding rock, pre-existing fractures approximately propagate straightforward along their initial directions and finally form planar fracture surfaces. Regarding in-situ stresses, with acute intersection angle between fracture and wellbore, fractures propagate toward the direction of the minimum principal stress. Besides, two parallel and opposite fractures individually arising from two parallel and non-coincidence wellbores always propagate towards each other after passing by each other. Moreover, the interactions between them become strengthened as the distance between them decreases. Finally, the propagating sequences of hydraulic fractures arising from a group of parallel wellbores are discussed. It is found that the sequence can influence the fracture geometry and previously propagated fractures can restrain the nearest fractures embedded in other wellbores propagating away from each other in subsequent stages. Highlights • 3D fractures arising from the sidewall of wellbore are studied via High-order GFEM. • Effect of intersect angle between fracture and wellbore on fracture path is studied. • Fractures with acute angles always propagate normal to the minimum in-situ stress. • Fractures are verified to propagate normal to each other after passing each other. • Fractures in previous stage restrain the deviation of fractures in subsequent stage. [ABSTRACT FROM AUTHOR]

Railway level crossings (RLCs) in Poland are classified according to their protection systems. Category D, which is a form of passive RLC, aims to ensure safe and efficient operation. Surveying is essential to prepare and control the geometry of the visibility triangles used at RLCs. This article presents a new approach to monitoring the geometry of visibility triangles of RLCs using an electronic total station and a magnetic measuring square (MMS). Its main assumptions are presented together with the application of the innovative measuring instruments. Visibility is demonstrated taking into account the angles of intersection of the road axis with the track axis of the railway line and additional attributes related to the analysis and evaluation of general visibility conditions. The research highlights controversies that have received special attention against the background of the safety status of railway level crossings. As a case study, the RLC located on a single-track railway line in Poland is examined. The final section presents applications of the results obtained according to the proposed methodology. It is shown that the proposed approach is practical and effective. In addition to surveyors, the survey methodology can be used by road and rail traffic engineers and policy makers to further improve traffic safety at RLCs. This is an important global research task.

Safety in highways is one of the most important subjects in Transportation Engineering. Increasing rate of vehicles and the needs to design or geometrically modifying the highways, emphasized on the safe-designing of the roadways more than before. Between the constructive components of the highway, horizontal curves due to the more occurrences of accidents are of great importance. The American ministry of highway and transportation introduced the software IHSDM, with variant capabilities, to predict accidents. In this research, five types of curves (simple circle curve and clothoid-circle-clothoid) at different intersection angles were designed, and accident rates based on the standard specifications on each curve was predicted by using the IHSDM, and the results are compared with each other. Finally, by processing the curves of accident rates versus the curves types and intersection angle, and comparing them with each other, the necessity of using spiral curves in the highway design is emphasized.

Characterization of hydraulic properties of crossed fractures is a key issue in understanding flow behavior of rock masses with complex fracture networks, which is of primary importance for many geoengineering practices. The effects of fracture intersection on fluid flow through 3D crossed rough-walled fractures in a linear flow regime were investigated by numerical simulations. A self-developed finite volume code was employed to solve the Navier–Stokes equation in 3D crossed fracture models. Different synthetic fractures were generated based on the data collected from three natural fracture surfaces. A series of numerical models were established by intersecting the different generations of the synthetic fractures to study the effect of surface roughness, intersection angle, intersection length, and scale on fluid flow through crossed rough-walled fractures. To evaluate the intersection effects, the effective transmissivity of the fracture segments, T eff , which is defined as the transmissivity affected by fracture intersection, was compared with the actual transmissivity of the fracture segments, T a. The results showed that the ratio of T eff / T a fluctuates more severely for the models with rougher fracture surfaces due to the formation of more complex geometry at fracture intersection. The ratio tends to reach a converged magnitude at large intersection lengths but with a wider ranges of variation for the models with rougher fracture surfaces. The results also showed that beside the complex geometry of intersection, the difference in the ratio of the mean aperture of the intersection facet to the actual hydraulic aperture of the corresponding fracture segment between different fracture segments may have an even more significant impact on the fluid flow in crossed fractures. The intersection angle affects the fluid flow through crossed fractures by altering the geometrical characteristics of the intersection in a heterogeneous manner, which stems from random nature of fracture surface roughness. The effects of intersection angle become negligible at large intersection lengths. The simulation results suggest one of the conditions to ignore the intersection effects on flow behavior of large-scale rough-walled fracture networks when flow is in a linear regime. Accordingly, all the fracture lengths in the fracture network should be larger than REV size of the fractures. • Geometrical characteristics of fracture intersection significantly affect fluid flow. • Intersection angle affects fluid flow in a heterogeneous manner. • Effects of intersection decrease with increasing intersection length. • Effects of intersection are negligible at fracture lengths larger than REV size. [ABSTRACT FROM AUTHOR]

Nonparallel support vector machine based on one optimization problem (NSVMOOP) aims at finding two nonparallel hyper-planes by maximizing the intersection angle of their normal vectors w and w . As maximum intersection angle preserves both compactness and separation of data, NSVMOOP yields good forecasting accuracy. However, as it solves one large quadratic programming problem (QPP), it costs high running time. In order to improve its learning speed, a novel nonparallel least square support vector machine (NLSSVM) is proposed in this paper. NLSSVM solves a linear system of equations instead of solving one large QPP. As both intersection angle and least square version are applied on our NLSSVM, it performs better generalization performance than other algorithms. Experimental results on twenty benchmark datasets demonstrate its validity. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing is commonly used as a main stimulation method in unconventional reservoirs in which interlayers are common and they may change the local stresses and permeability. Interlayers with different intersection angles with the principal stresses may have different initial stress and permeability, and the hydraulic fracture approaches the interlayer from different angles. In this research, finite element based numerical analysis of hydraulic fracturing has been carried out to study the stress and permeability variation within interlayers of four different intersection angles. The stresses and permeability variation shows that: (1) the intersection angle not only influences the stress and permeability of the interlayer, but also determines the timing for the fracture to reach and/or pass the interlayer; (2) the hydraulic fracturing process also influences the stress and permeability within the interlayer, and the higher the intersection angle is, the higher the stress-coupled permeability is. The results can help us to better understand the influence of intersection angle on the mutual effect between interlayer and hydraulic fracturing quantitatively towards an optimal design of hydraulic stimulation process. [ABSTRACT FROM AUTHOR]

In this paper, the field synergy principle is firstly performed on the viscoelastic fluid-based nanofluid and other relevant fluid in channel at turbulent flow state to scrutinize their heat transfer performance based on our direct numerical simulation database. The cosine values of intersection angle between velocity vector and temperature gradient vector are calculated for different simulated cases with varying nanoparticle volume fraction, nanoparticle diameter, Reynolds number and Weissenberg number. It is found that the filed synergy effect is enhanced when the nanoparticle volume fraction is increased, nanoparticle diameter is decreased and Weissenberg number is decreased, i.e. the heat transfer is also enhanced. However, the filed synergy effect is weakened with the increase of Reynolds number which may be the possible reason for the power function relationship in empirical correlation of heat transfer between heat transfer performance and Reynolds number with the constant power exponent lower than 1. Finally, it is also observed that the field synergy principle can be used to analyze the heat transfer process of viscoelastic fluid-based nanofluid at the turbulent flow state even if some negative cosine values of intersection angle exist in the flow field. [ABSTRACT FROM AUTHOR]

The influence of dip directions on the main deformation region of layered rock around tunnel is studied using a 3D distinct element code called 3DEC. We learn that the main deformation regions around tunnels are regularly changeful along with different intersection angles between dip direction and advancing direction of the tunnel. The specific deformation regions can be anticipated based on detailed engineering geological survey before tunnel excavation. Moreover, the common deformation pattern around tunnels is found to be structural deformation including bending and slipping of layered rock. The main deformation region is prone to occur at the region where the normal direction of rock layer points to the inside of tunnel because the minimum tensile strength of bedding plane appears on this region and rock bending is generally easier than rock slipping. An understanding of the main deformation regions around tunnels provides critical information for selecting the route of a tunnel, forecasting the main deformation region and designing an efficient support system. [ABSTRACT FROM AUTHOR]

Abstract: The gas flow fields of four atomizers were analyzed by both k–ɛ turbulence model and Reynolds stress turbulence model (RSM). The scattering angle of the main part of gas spray increased from 15.0° to 17.4° given by k–ɛ model and 17.2° to 19.0° given by RSM model, as the nozzle intersection angle increased from 5° to 65° at the operating gas pressure of 1.0MPa, which also moved the merging position of the annular peak. There is a high pressure area downstream of the delivery tube which contributes to the sheet breakup. Comparing the simulation results with the experimental data, it is found that RSM model is more accurate than k–ɛ model and proved that computational fluid dynamics is an effective method to simulate the gas flow of the close coupled atomizer. [Copyright &y& Elsevier]

In this paper the lattice Boltzmann method and field synergy principle are applied to simulate two-dimensional incompressible steady channel flow under low Reynolds number, and analyze the local influence on velocity field and temperature field caused by inserting cylinder obstacles of different cross-section. Furthermore, field synergy principle of elliptic flow type is applied to demonstrate that the increased interruption within the fluid increases the synergistic level between the velocity field and temperature gradient field. As the intersection angle between the velocity vector and the temperature gradient vector decreases by inserting cylinder obstacles to fluid field, the results of heat transfer will improve significantly. [ABSTRACT FROM AUTHOR]

The dynamic behavior of optical modulators/switches in the form of intersecting waveguides with curved electrodes is formulated. It is shown that the electrode curvature is very effective in achieving reflected pulses in good resemblance to the incident ones. Further, the speed of operation is found to be high and is shown to depend upon the commonly known capacitance of the device and the time required for refractive index variations to settle down; and also upon the relative pulsewidths of the optical and modulating signals and the extent of their synchronization. The intersection angle is found to influence the propagation delays of the spatial components, which are equalized by properly chosen structural parameters, to achieve unbroadened and undistorted output pulses. The flexibility in the bandwidth of even a fabricated device, through adjustment of the driving conditions, is demonstrated and the capability of such devices to handle a very wide range of optical pulsewidths is clarified [ABSTRACT FROM PUBLISHER]

Railway level crossings (RLCs) in Poland are classified according to their protection systems. Category D, which is a form of passive RLC, aims to ensure safe and efficient operation. Surveying is essential to prepare and control the geometry of the visibility triangles used at RLCs. This article presents a new approach to monitoring the geometry of visibility triangles of RLCs using an electronic total station and a magnetic measuring square (MMS). Its main assumptions are presented together with the application of the innovative measuring instruments. Visibility is demonstrated taking into account the angles of intersection of the road axis with the track axis of the railway line and additional attributes related to the analysis and evaluation of general visibility conditions. The research highlights controversies that have received special attention against the background of the safety status of railway level crossings. As a case study, the RLC located on a single-track railway line in Poland is examined. The final section presents applications of the results obtained according to the proposed methodology. It is shown that the proposed approach is practical and effective. In addition to surveyors, the survey methodology can be used by road and rail traffic engineers and policy makers to further improve traffic safety at RLCs. This is an important global research task. [ABSTRACT FROM AUTHOR]

This article investigates the dynamics of droplet generation process in a microfluidic flow-focusing device under the effect of geometry altered by the intersection angle (φ), which the flanking inlets make with central inlet and wall wettability quantified by the contact angle (θ) using volume of fluid (VOF) model. These parameters have been found to alter the droplet shape and size greatly. The effect of intersection angles has been examined for φ = 15 deg, 30 deg, 45 deg, 60 deg, 90 deg, and 120 deg for generating size-controlled droplets. It was predicted that the diameter of droplet increased with the increase in intersection angle (φ = 15 deg, 30 deg, 45 deg, 60 deg, 90 deg, and 120 deg) and the maximum diameter has been generated at φ = 90. In addition, the wetting characteristics (hydrophilic to hydrophobic) have been studied numerically in detail by changing the contact angle of the dispersed phase with the channel wall ranging from 90 deg to 180 deg. It was indicated that the droplets of rectangular shape are formed in hydrophilic channel by completely wetting the wall when θ ≤ 90 deg. They transform their shape to slightly oval form with the increase in contact angle and start acquiring spherical shape when the channel becomes hydrophobic. Furthermore, Parameters such as dimensionless droplet diameter, droplet shape, and droplet breakup time have also been investigated extensively for flowrate ratios Q = 0.125, 0.25, 0.5, and 1, in order to optimize the microfluidic device. [ABSTRACT FROM AUTHOR]

Realistic discontinuity network modelling of rocks requires the accurate input of the three-dimensional discontinuity orientation distribution (3DDOD), but in practice, access to such three-dimensional information is limited. Fouché recently developed a method for estimating the 3DDOD from one-dimensional scanline-mapping observations. However, little is known about the error in such 3DDOD estimates. This study focuses on (1) the error and its possible contributors, (2) error prediction, and (3) error mitigation. An error investigation based on synthetic discontinuity geometry data reveals that the 3DDOD estimates are not always accurate. The error is significantly impacted by three factors: the Fisher constant (к), the angle between the major discontinuity plane and the mapping scanline (θ), and the discontinuity sample size (n), with larger к , θ , or n values contributing to lower errors. This к -, θ -, and n- dependent error appears to be inherently related to the sample density, which is defined as the pole number per unit cell (1° × 1°) in the Fouché method. Additionally, a predictor of the error based on an error-and-factors empirical relationship is developed to provide precise error prediction and optimize the scanline sampling for error mitigation. The weakness of the developed predictor is also disclosed. [ABSTRACT FROM AUTHOR]

While individuals with disabilities constitute a significant portion of the population in the United States, they are often neglected in pedestrian studies due to lack of available data. Understanding the relationships among heterogeneous pedestrian flow characteristics involving individuals with and without disabilities can improve the design and planning for walking facilities. The objective of this research is to propose a density–speed model for a bidirectional pedestrian stream and examine it for various walking environments with different intersecting angles (90°, 135°, and 180°). To calibrate the proposed model, a set of large-scale controlled walking experiments was conducted at Utah State University and various one-directional and bi-directional flow combinations were examined. The properties of the calibrated model indicated that interaction effects drop with increases in walking facility angle. Moreover, the capacity of walking facilities is reduced with increases in the structure angle. Specifically, the results revealed that 180°, 135°, and 90°operate at 78%, 79%, and 82% of maximum capacity under a balanced bi-directional flow. • A density–speed model is proposed, which captures the impacts of facilities' angles. • Data collected in a large scale walking experiment were used to calibrate the model. • Decreases in intersecting angle result in more interactions between pedestrians. [ABSTRACT FROM AUTHOR]