Intersection Angle Research Articles

Station Arrangement Optimization of Photoelectric Theodolites Based on Efficient Traversing Discrete Points

Station arrangement optimization of photoelectric theodolites in shooting ranges presents a non-convex and non-linear problem, and the method required to seek the global optimal solution remains an open question. This paper proposes an efficient traversal algorithm that could solve this problem by utilizing discretization of regions with a finite length of mesh, in which both the terrain of the station arrangement region and the observation airspace region are discretized through triangulation. To enhance the computational efficiency of the traversal algorithm, two strategies are employed to speed up the calculation: reducing the dimension of the observation airspace and using the Euclidean distance matrix to compute the intersection angle. After the global optimal solution with discrete finite precision was obtained through the traversal algorithm, it was then used as the initial points for local mesh refinement and to implement gradient-based optimization in order to further improve the precision of the solution. The proposed approach is demonstrated to be practical through application to numerical examples used for the optimization of station arrangements that involve two to four stations.

A Target Damage Effectiveness Assessment Mathematical Calculation Method with Uncertain Information Based on an Adaptive Fuzzy Neural Network

Aiming to address the issue of assessing the effectiveness of target damage in air defense interception under projectile and target intersection, this paper proposes a novel target damage effectiveness assessment mathematical calculation method using an adaptive fuzzy neural network. The design and calculation methods introduce the target cabin’s damage weight factor, the dispersion error and coverage density and fire density of warhead fragment, and the ratio of the number of warhead fragments to the cross-sectional area of the target as the primary damage factors, and we establish a new model for calculating the target damage efficiency using Takagi-Sugeno adaptive fuzzy neural network with the multiple damage factors. In the designed model, we take the characteristic parameters of warhead fragments formed by the projectile explosion as the sample data and learn the mapping relationship between damage factors and damage effect expressed by the system of fuzzy rule. Combined with the vulnerability weight and damage factors of the target, the fuzzy rule system is applied to predict and calculate the damage probability and damage effectiveness. In addition, we use shot-line technology to set up the intersection criterion between warhead fragments and target, analyze the coordinate relationship of the projectile explosion relative to the target based on the ground coordinate system, and derive the distribution density function of warhead fragment and research a calculation model for target damage probability with multiple vulnerable cabins. Finally, we use the established model to train, test, and calculate the data from the actual projectile and target intersection damage test and present the comparison results to other damage calculation methods. By calculation and comparative analysis, the results show the smaller the distance between projectile and target, as well as the smaller the average intersection angle, and the larger the weight coefficient of the warhead fragment covering the target cabin, the total target damage probability increases obviously. In the two experimental calculations, the target cabin with the largest weight coefficient was considered, and compared with the existing literature, the damage probability of the proposed calculation method was increased by 9.13% and 10.93%, respectively, and it is clear that the proposed target damage assessment method can effectively reflect the real target damage effectiveness in the state of projectile and target intersection.

Learning curves for point-of-care ultrasound image acquisition for novice learners in a longitudinal curriculum

BackgroundA learning curve is graphical representation of the relationship between effort, such as repetitive practice or time spent, and the resultant learning based on specific outcomes. Group learning curves provide information for designing educational interventions or assessments. Little is known regarding the learning curves for Point-of-Care Ultrasound (POCUS) psychomotor skill acquisition of novice learners. As POCUS inclusion in education increases, a more thorough understanding of this topic is needed to allow educators to make informed decisions regarding curriculum design. The purpose of this research study is to: (A) define the psychomotor skill acquisition learning curves of novice Physician Assistant students, and (B) analyze the learning curves for the individual image quality components of depth, gain and tomographic axis.ResultsA total of 2695 examinations were completed and reviewed. On group-level learning curves, plateau points were noted to be similar for abdominal, lung, and renal systems around 17 examinations. Bladder scores were consistently good across all exam components from the start of the curriculum. For cardiac exams, students improved even after 25 exams. Learning curves for tomographic axis (angle of intersection of the ultrasound with the structure of interest) were longer than those for depth and gain. Learning curves for axis were longer than those for depth and gain.ConclusionBladder POCUS skills can be rapidly acquired and have the shortest learning curve. Abdominal aorta, kidney, and lung POCUS have similar learning curves, while cardiac POCUS has the longest learning curve. Analysis of learning curves for depth, axis, and gain demonstrates that axis has the longest learner curve of the three components of image quality. This finding has previously not been reported and provides a more nuanced understanding of psychomotor skill learning for novices. Learners might benefit from educators paying particular attention to optimizing the unique tomographic axis for each organ system.

Study on the Mechanical Response of a Dense Pipeline Adjacent to the Shallow Tunnel

This paper aims to address the issue of disturbance caused by excavation tunnel construction on nearby dense pipelines. Relying on the actual project of Nanchang Metro, the three-dimensional finite element numerical simulation method is used to establish a multi-condition numerical model. At the same time, key influencing factors such as the clear distance, intersection angle, surrounding rock parameter, and construction method are considered. The mechanical response of the dense pipeline adjacent to the dug tunnel was systematically studied, and the influence of key factors on the mechanical behavior of the pipeline was analyzed. The results show that when using the CRD method for construction and grouting reinforcement of the surrounding strata of the tunnel, the maximum settlement of the vault is located at the vault of the right guide tunnel, and the maximum settlement value is located at the bottom of the rainwater pipe directly above the tunnel. The vertical displacement, maximum principal stress, and minimum principal stress of the pipeline are arranged in descending order for the full-face, stepped method, and CRD method. The greater the disturbance to the soil caused by the construction method, the more unfavorable the effect on the pipeline.

Microscopic coalescence mechanism of nanoparticle-laden droplet pairs in the coupling of electric field and flow field: A molecular dynamics study

Electrocoalescence is a time-saving and energy-efficient technology for dehydrating crude oil. The microscopic coalescence mechanism of nanoparticle-laden water droplet pair in the coupling of electric field and flow field was studied by molecular dynamics simulations. The present numerical results agreed well with the experimental work in the literature and the theoretical predictions. The effects of electric field strength and direction, flow field strength and type, droplet intersection angle, and multiple droplets on nanoparticle-laden droplet pair coalescence in the coupling fields were systematically discussed. The results illustrate that four coalescence modes occurred in the coupling of electric field and shearing flow field (E&S coupling fields), and the coalescence efficiencies ranked as: rolling coalescence mode > temporary coalescence mode > stretching mode > slipping mode. Electric fields dominate droplet coalescence, while flow fields enhance droplet coalescence in the coupling fields. Furthermore, parallel direction of electric field and flow field generally leads to high coalescence efficiencies. As to the multiple droplet systems, in the coupling of x-axis electric field and rotating flow field (E&R coupling fields), the coalescence efficiencies ranked as structure I > structure IV > structure III > structure II, whereas, in the y-axis E&R coupling fields, the coalescence efficiencies ranked as structure I > structure III > structure IV > structure II. Finally, the coalescence efficiencies of the E&R coupling fields were always higher than those of the E&S coupling fields. The results will be potentially valuable for optimizing the design of compact and efficient crude oil dehydrators.

Crystal plasticity-based analysis and modelling of grain size and strain path dependent micro-scaled deformation mechanisms of ultra-thin sheet metals

Multi-stage microforming is increasingly used in manufacturing of the miniaturized parts with complex structures and geometries. Optimization design of this type of manufacturing process, however, is still challenging due to its unknown intrinsic nature of the process. In the multi-stage deformation and microforming, the size effect (SE), the strain path change (SPC), and the intragranularly misoriented grain boundary (IMGB) generated in previous forming stage, are the main factors governing the deformation behaviors of ultra-thin sheets. To gain thorough insights into their influences on deformation and elucidate the associated micro-scaled mechanisms, SS 316L ultra-thin sheets with the thickness of 0.1 mm and different mean grain sizes (d¯) were used for two-stage tensile tests under the conditions with distinct pre-strain εpre and intersection angle θSPC (the angle between the previous loading direction and subsequent one). Mechanical tests reveal that increasing εpre and θSPC reduces the yield stress and hardening rate in SPC tension, but this reduction gets smaller after increasing d¯. This is because more IMGBs with complex pattern are formed in relatively large grains, raising the permanent deformation resistance inside grains in subsequent tension. To model the IMGB-induced hardening, the SPC-induced softening, and the SE-induced concurrent facilitations to the hardening and softening, an enhanced crystal plasticity constitutive relation was established. The physical essence that IMGB obstructs dislocation movement, is used to model the IMGB-induced hardening based on the interactions between the main slip planes and IMGBs. The hardening facilitation caused by increasing grain size is implicitly incorporated in determining the saturated slip resistance. Modelling of the SPC-induced softening is based on the high Schmid factor grain fraction and its influences are governed by pre-strain and the defined SPC parameter. The softening facilitation caused by coarsening grains is modelled in establishing the initial slip resistance in SPC deformation. The proposed simulation procedure and constitutive relationship help with accurately predicting the mechanical response and microstructure evolution in micro-scaled SPC deformation, and also provide a basis for modelling and design of the multi-stage microforming of complex miniaturized parts.

Discrete Fracture Network (DFN) Analysis to Quantify the Reliability of Borehole-Derived Volumetric Fracture Intensity

Volumetric fracture intensity (P32) is a parameter that plays a major role in the mechanical and hydraulic behaviour of rock masses. While methods such as Ground Penetrating Radar (GPR) are available to map the 3D geometrical characteristics of the fractures, the direct measurement of P32 at a resolution compatible with geotechnical applications is not yet possible. As a result, P32 can be estimated from the borehole and surface data using either simulation or analytical solutions. In this paper, we use Discrete Fracture Network (DFN) models to address the problem of estimating P32 using information from boreholes (1D data). When calculating P32 based on Terzaghi Weighting, it is common practice to use drill run lengths and limit the minimum angle between the borehole and the intersected fractures. The analysis presented in this paper indicated that limiting the minimum angle of intersection would result in an underestimation of the calculated P32. Additionally, the size of the interval has a significant impact on the variability of the calculated P32. We propose a methodology to calculate P32 using variable lengths, depending on the angle between the fractures and the borehole. This methodology allows the capture of the spatial variation in intensity and simultaneously avoids artificially increasing or decreasing the intensity sampled along borehole intervals. Additionally, this work has addressed the impact of boundary effects in DFN models and proposes a methodology to mitigate them.

A criterion for a hydraulic fracture crossing a natural fracture in toughness dominant regime and viscosity dominant regime

Hydraulic fracturing is an efficient stimulation technology in the process of unconventional reservoir development, and the hydraulic fracture morphology directly affected oil and gas recovery. In this paper, we proposed a new criterion based on linear elastic fracture mechanics (LEFM) to predict the intersection behavior of hydraulic fracture (HF) and natural fracture (NF) with non-orthogonal angle. The new criterion considered the coupling effects of the fluid flow, stress shadow, and poroelastic response, and was validated with published analytical criteria and laboratory tests. Sensitivity analysis results indicated that an HF tends to cross NF under conditions of short HF half-length, high friction coefficient, high fracturing fluid viscosity and high fracture toughness. In addition, high principal stress difference inhibited the crossing behavior when the intersection angle was less than the transition angle, the HF would be arrested or divert along NF.

Mach–Zehnder-like interferometry with graphene nanoribbon networks

We study theoretically electron interference in a Mach–Zehnder-like geometry formed by four zigzag graphene nanoribbons arranged in parallel pairs, one on top of the other, such that they form intersection angles of 60∘. Depending on the interribbon separation, each intersection can be tuned to act either as an electron beam splitter or as a mirror, enabling tuneable circuitry with interfering pathways. Based on the mean-field Hubbard model and Green’s function techniques, we evaluate the electron transport properties of such eight-terminal devices and identify pairs of terminals that are subject to self-interference. We further show that the scattering matrix formalism in the approximation of independent scattering at the four individual junctions provides accurate results as compared with the Green’s function description, allowing for a simple interpretation of the interference process between two dominant pathways. This enables us to characterize the device sensitivity to phase shifts from an external magnetic flux according to the Aharonov–Bohm effect as well as from small geometric variations in the two path lengths. The proposed devices could find applications as magnetic field sensors and as detectors of phase shifts induced by local scatterers on the different segments, such as adsorbates, impurities or defects. The setup could also be used to create and study quantum entanglement.

Аналитическая модель равноканального углового прессования титановой губки

Introduction. The use of equal-channel angular pressing (ECAP) of metal powder makes it possible to obtain practically non-porous blanks with high hardness, with a high level of accumulated deformation and with the formation of an ultra-fine-grained structure. A relevant issue for the study of the semi-continuous ECAP process remains a reliable assessment of the energy-power parameters of the process and the prediction of the porosity of compressed materials. This, in turn, is due to the need to develop sufficiently accurate, reliable and simple mathematical models for practical application. The purpose of the work is to develop an analytical model of the process of equal-channel angular pressing of porous material. Powdered screening of spongy titanium of the TG-100 brand was selected as a model of the material for the study. The object of the study is the process of semi-continuous equal-channel angular pressing of axisymmetric porous briquette of titanium sponge in the channel of the mold. It is assumed that the ECAP uses a punch to create back pressure. For the solution, a process scheme, a statically permissible load scheme on a layer of intense deformation and a kinematically permissible flow scheme of a plastically compressible medium in a layer are determined. A system of equations is constructed in accordance with the accepted schemes. The equation power balance is applied. The analytical equation is solved by the method of successive approximations. Finite element simulation of the porous titanium ECAP process was carried out at the angles of intersection of the mold channels at 45°, 50°, 55° and 60°. Results and Discussion. The porosity of the blank is determined at different stages of the ECAP process. A diagram of the change in pressure on the punch using the analytical solution and finite element simulation is obtained. It is revealed that the results of the analytical solution are consistent with the data of the finite element simulation. The highest stress level occurs in the process of equal-channel angular pressing at α = 45°, however, the distribution of relative density over the cross section is most uniform. The maximum value of the pressure on the working punch decreases with an increase in the angle α. Rational technological parameters of pressing porous blanks should provide the maximum permissible pressure on the deforming tool. From this condition, in each specific ECAP process, it is possible to determine the optimal angle value from the analytical solution.

Numerical simulation of near wellbore fracture propagation in interbedded continental shales with competing perforations

To reduce near wellbore fracture complexity in continental laminated shales, in-plane perforations completion technology is introduced. The global embedded cohesive elements are capable to simulating arbitrary fracture propagation growth while the laminae effects on fracture propagation path can be considered in established finite element model. Numerical simulations reflect that the existence of weak micro fractures only locally alter the fracture propagation path but laminae can change the fracture propagation path greatly. Furthermore, the in-situ stress anisotropy, pump rate, perforation intersection angle and perforation angle with laminae are critical factors for affecting the fracture propagation path and breakdown pressure. There is a great impact of laminae on the fracture branching at the contact interface and hydraulic fracture tends to cross laminae at high approaching angle but propagate horizontally along laminae at low approaching angle. In most cases, hydraulic fracture tends to propagate along the laminae rather than across the laminae. The adjustment of pump rate, fluid viscosity, perforation intersection angle and perforation angle with laminae can enhance the possibilities of hydraulic fracture across laminae. It was also found that hydraulic fractures induced from different perforations can interact and overlap with each other, resulting in different fracture geometry and pressure behavior for individual fracture. The fracture width of interior fracture is almost close at the near wellbore zone at the end of pumping, and exterior fractures generally deviated away from the perforation tunnel direction because of stress interference of neighboring fractures. Additionally, although a fracture initiated initially from a perforation tunnel to short distance, hydraulic fractures still finally would reorient itself to maximum principle in-situ stress direction, thus increase more chances of creating one large and main fracture along the maximum principle in-situ stress orientation with larger horizontal stress contrast. Therefore, the existence of laminae can enhance the potential of fracture complexity near wellbore but the selection of suitable perforation scenarios in one defining plane can increase the possibility of form a main fracture. The simulation results from this study offer some important insights to hydraulic fracturing design with multiple perforations on interbedded continental shales stimulation.

ICESat-2 river surface slope (IRIS): A global reach-scale water surface slope dataset

The global reach-scale “ICESat-2 River Surface Slope” (IRIS) dataset comprises average and extreme water surface slopes (WSS) derived from ICESat-2 observations between October 2018 and August 2022 as a supplement to 121,583 reaches from the “SWOT Mission River Database” (SWORD). To gain full advantage of ICESat-2’s unique measurement geometry with six parallel lidar beams, the WSS is determined across pairs of beams or along individual beams, depending on the intersection angle of spacecraft orbit and river centerline. Combining both approaches maximizes spatial and temporal coverage. IRIS can be used to research river dynamics, estimate river discharge, and correct water level time series from satellite altimetry for shifting ground tracks. Additionally, by referencing SWORD as a common database, IRIS may be used in combination with observations from the recently launched SWOT mission.

Interactive piecewise planar building reconstruction from a single image based on geometric priors

The development of methods to reconstruct the piecewise planar structures of buildings from a single image is an important and challenging problem in the field of computer vision. Although most prior works have considered fully automatic reconstruction solutions, these methods typically perform poorly for complex building structures. To address this problem, we propose an interactive single-image 3D building reconstruction method to integrate automatic plane inference with interactive plane refinement based on geometric priors. In this method, based on geometric priors (e.g., the orientation of the plane and the intersection angle between planes) learned using convolutional neural networks, building regions are first partitioned into multiple polygonal regions using click interactions. Then, the planes corresponding to these polygonal regions are automatically and progressively inferred by taking full advantage of the constraints constructed using the geometric priors. Finally, under the guidance of interactive plane refinement based on click correlations, the resulting planes are globally optimized by jointly utilizing image cues and geometric priors. The results of an experimental evaluation on three datasets demonstrate that the proposed method achieved better performance than existing methods in terms of both qualitative and quantitative measures.

Morphology and molecular phylogeny of Pleurosigmapacificum sp. nov. (Pleurosigmataceae), a new tropical pelagic species from the Western Pacific Ocean.

A new species of pelagic diatom, Pleurosigmapacificumsp. nov., is described from the tropical Western Pacific Ocean. It has the typical features of Pleurosigma, including a slightly sigmoid raphe, intersected transverse and oblique striae, and loculate areolae with external opening slits and internal poroids. Morphologically, P.pacificum belongs to a species group of Pleurosigma with lanceolate valves, including P.atlanticum Heiden & Kolbe, P.nubecula W. Smith, P.indicum Simonsen, and P.simonsenii Hasle. However, P.pacificum differs by its smaller lanceolate valve and smaller intersection angle as well as elliptical areolae without a silica bar. The SSU rDNA and rbcL sequence data place P.pacificum in a basal position relative to other species of Pleurosigma. Our molecular phylogenetic analyses did not support the monophyly of lanceolate and slightly sigmoid species. Thus, the sigmoidality of valve outline cannot be considered as a criterion to define the species group.

Conflict resolution in the case of convective weather cell circumvention

This research analyzes the area required for the conflict resolution between aircraft in two flows impacted by a convective weather cell (CWC). The CWC is introduced as a constrained area, forbidden to flight through, which affects the air traffic flows. Prior the conflict resolution, two flows and their intersection are relocated away from the CWC area (thus enabling circumvention of the CWC), which is followed by a tuning of the relocated flows intersection angle in order to create the minimal size of the conflict zone (CZ—a circular area centered at the intersection of two flows, which provides aircraft enough space to completely resolve the conflict within). Therefore, the essence of the proposed solution is in providing conflict free trajectories for the aircraft in intersecting flows that are affected by the CWC, with the goal of minimizing the CZ size, so the finite occupied airspace for the conflict resolution and the CWC circumvention could be reduced. Compared to the best solutions and current industry practice, this article is focused in reduction of the airspace required for aircraft to aircraft and aircraft to weather conflict resolution, and not to distance travelled, time savings, and fuel consumption minimization. The conducted analysis in the MicrosoftExcel2010 confirmed the relevance of the proposed model and demonstrated variations in efficiency of the utilized airspace. The proposed model's transdisciplinary nature makes it potentially applicable in other fields of study, such as the conflict resolution between unmanned aerial vehicles (UAVs) and fixed objects like buildings. Building on this model and taking in consideration large and complex data sets, such as weather related data and flight data (aircraft position, speed, and altitude), we believe it is possible to conduct more sophisticated analyses that would take advantage of Big Data.

Exploratory quantification of 3D spatial competition in ecotone of trees and bamboos using terrestrial laser scanner

With the intrinsic advantages of fast growth, high fecundity, diversity of forms, and group synergy, bamboos have been rapidly spreading in China and abroad. The spatial invasion of bamboo is actually the outcome of unbalanced competition between trees and bamboos. However, there is currently no competition index (CI) specially designed to quantitatively analyze the 3D spatial competition occurring between trees and bamboos. In this study, the point cloud data of the sample plot at the ecotone of trees and bamboos was scanned using a terrestrial laser scanner (TLS). The structure parameters of individual trees and bamboos were first extracted after point clustering and segmentation. Then, the survival intersection angle index (SAI) was constructed to incorporate the height difference and diameter at breast height (DBH) ratio of trees and bamboos. The crown distance index (CDI) was used to measure the serious mechanical damages made by bamboo culms to tree crowns. The final survival index (SI) was the output of direction-weighted sub SIs in four directions around objective trees. As a result, the final SIs of Masson pines in study site ranged from 0.48 to 1.0, indicating most tree crowns had been seriously intruded by Moso bamboo culms. The minimum final SI was caused by group-synergetic pressure exerted by competitive bamboos around. Therefore, the final SI calculated using the snapshot point cloud was applicable for evaluating the tentative survival statuses of objective trees in the ecotone, and helpful for analyzing the potential of bamboo spatial invasion.

Exceptionally Strong Self-Powered Polarization Behaviors Involving with Bulk Photovoltaics in Highly Anisotropic 2D Hybrid Perovskite Ferroelectric Crystals

Two-dimensional (2D) hybrid perovskites take an emerging position in optoelectronics. Especially, ferroelectric crystals in this family can be potentially used as polarized light detectors because photocurrent, induced by the ferroelectric bulk photovoltaic effect (BPVE), is the function of the intersection angle between the polarization directions of polarized light and the spontaneous polarization (Ps) direction of ferroelectric crystals. Herein, exceptionally strong polarization responses to polarized light are achieved in ferroelectric crystals of (isopentylammonium)2CsPb2Br7 (1), which is closely involved with the Ps-directed BPVE. Structurally, the alternate packing of organic spacers and inorganic sheets leads to its intrinsic anisotropy of optical dichroism (αc/αa ∼ 3.1), thus creating sinusoidal photocurrents with a polarization ratio of ∼1.2 at 10 V bias. It is noteworthy that the exceptional polarization responses with a large polarization ratio of ∼7.2 can be further obtained based on its BPVE at zero bias (self-powered mode). This figure-of-merit is significantly superior to that of some 2D materials, nanowires, and homologues, e.g., ReS2 (∼3.5), GeSe (∼2.16), CsPbBr3 nanowire (∼2.6), and (n-butylammonium)2(methylammonium)Pb2Br7 (∼2.0). This work sheds light on the optimization of photoelectric behaviors on the targeted optoelectronic device applications by ferroelectric BPVE.

Thermal and hydraulic characteristics of a new proposed flyover-crossing fracture configuration for the enhanced geothermal system

An advanced enhanced geothermal system (EGS) is capable of unlocking many thousands of megawatts of power in hot dry rocks, and the fracture configuration is a critical factor influencing its efficiency. A flyover-crossing fracture (FCF) configuration for EGS was proposed in this paper, to enhance heat transfer between the working fluid and reservoir and thus the productivity of EGS. A 3D transient thermal-hydraulic model was established to analyze the heat extraction of the FCF-EGS, and the effects of intersection angles of the FCF on the heat and mass transfer as well as the productivity of the EGS were examined. The FCF-EGS was found to bring higher production temperature and thermal power output than the conventional double-horizontal-well EGS during a 30-year heat recovery period, and the heat extraction capacity of the FCF-EGS was found to increase with the intersection angle. It was also found that the FCF with a 90°cross-angle has the best heat extraction performance, with the output thermal power increased by 5.12% compared to the conventional double-horizontal-well EGS, due to the enhancement of heat transfer between the working fluid and rock. Although this fracture system requires more investment in fracturing and larger pressure in production, the increase in heat production far outweighs this input. This study provides a novel potential fracture configuration for exploiting HDR geothermal energy.

Effect of the arrangement of two nozzles on morphology, velocity, and particle size distribution of artificial snow-making spray field

A decline in natural snow due to global warming increases the reliance of ski resorts on artificial snow. To improve the formation rate and snow amount of artificial snow under any environmental conditions, it is necessary to use atomization technology that maintains the size of liquid drops of the snow-making spray field below a critical size, thus maximizing the number of freezing droplets into ice crystals. Here, we study the effects of the gas–liquid mass-mixing ratio (GLR) and the spacing (d) between two nozzles on the characteristics of the snow-making spray field produced by atomization technology for GLR of 0.05, 0.10, 0.15, and 0.2 and d of 5, 10, 15, and 20 cm. The measurement of the morphology, velocity, and particle-size distribution of the snow-making spray field is conducted by a laser particle-size measuring instrument, particle image velocimetry, and a high-speed camera. Our results show that both the spray cone and the intersection angles increase with the increase in the GLR in a two-nozzle arrangement, while the degree of interference between the nozzles increases with the decrease in spacing, d. We also find that the inward offset of the spray is the main reason for the increase in the intersection angle and the interference area and the deviation of the spray midline. In addition, we compare the characteristics of the spray field produced by the single and the two-nozzle systems. We conclude that the flow-field velocity of the single nozzle is smaller than that of the two nozzles and the velocity gradient of the liquid drops in the two-nozzle flow field varies greatly. The maximum vorticity (Max = 147) in the case of the two-nozzle arrangement is much larger than that of the single nozzle. Moreover, by analyzing the two-nozzle flow field at different spacings, we find that the particle-size distribution is most uniform for GLR = 0.10 and d = 15 cm. Thus, our study elucidates the characteristics of spray fields suitable for snow-making toward achieving higher quality and more efficient snow-making processes.

3-D hydromechanical simulation of intersecting faults: Influences on fluid circulation and formation of oriented-orebodies

Although intersection zones of two or more fault arrays have been identified as favorable loci of unconformity-related basin-basement mineral deposits in previous studies, their roles in controlling fluid flow patterns related to formation of oriented-, and structurally-controlled mineral deposits remain unclear. In this study, 3-D hydromechanical models were conducted to better understand the response of a natural fault intersected by a hydraulic fault under different stress regimes. A comprehensive parametric study was carried out to assess the roles of fluid pressure, burial depth, basin permeability, intersection angle, and horizontal differential stress on the hydromechanical response of a system containing two intersecting faults. Depending on basin sediment permeability, fault intersection angle, and horizontal differential stress, the fluid flow either stops, crosses, or diverts toward natural fault. Among the tested parameters, the intersection angle, and horizontal differential stress have the most noticeable effect on the fluid flow in the system. The critical intersection angle at which the fluid flow diverts toward the natural fault varies between ≈27° in normal faulting regimes, to ≈55°, in both strike-slip and reverse faulting regimes. Conversely, burial depth and fluid pressure have no significant effect on fluid flow diversion in the intersection zone. The results are in agreement with field observations related to the unconformity-related uranium deposits found in northern Canada.