Angular Index Research Articles

3D characteristic indicator analysis and comprehensive evaluation of manufactured sand particles used in high-performance concrete

Two-dimensional particle morphology indices face challenges in accurately depicting the characteristics of three-dimensional (3D) manufactured sand (MS), which does not effectively guide the selection of MS for high-performance concrete (HPC). This study aimed to obtain a quantified comprehensive evaluation of actual MS particle groups with specific gradations by thoroughly analysing 3D geometric characteristics. Two representative MS samples were selected for exploration, and river sand (RS) was used as the control. A random selection of sand particles was screened on six sieve levels ranging from 0.15 mm to 4.75 mm. Using X-ray computed tomography and associated image processing technologies, 3D models of these particles were generated, and MATLAB was used to extract their 3D morphology information. Subsequently, the change rules and validity of current 3D particle morphology indicators were examined, focusing on shape, angularity, and texture. Moreover, a comprehensive morphology index, Cm, was proposed by considering the effects of gradation and particle shape classification. The results showed that shape indices more accurately reflected particle characteristics, notably, a higher proportion of spheroid particles, a lower aspect ratio, and greater sphericity correlated with improved particle shape; contrary to traditional beliefs, the angularity index suggested that greater roundness did not necessarily equate to more rounded particles owing to the influence of the proportion of spheroid and cubic particles; meanwhile, texture indices showed minimal difference in the mean values of the 3D fractal dimension for the three types of sand. The proposed index Cm effectively differentiated the particle morphology states of the three sands, with higher Cm values indicating superior particle morphology. The smaller the difference between the Cm values of MS and RS, the better substitute of MS for RS.

Influence of coarse aggregates’ morphological characteristics on the pore structures of skeleton in porous asphalt mixture

Coarse aggregates play a significant role in configuring the pore structures in the porous asphalt mixture (PAM). This study aims to reveal the influence of coarse aggregates’ morphological characteristics on the pore features in the coarse aggregate skeleton (CAS) of PAM. To achieve this goal, X-ray CT and three-dimensional (3D) visualization reconstruction technology were utilized to acquire the 3D morphology of different kinds of coarse aggregates. Based on the morphology of real aggregate particles, a 3D simulation model of CAS was developed, and virtual scanning imaging technology was used to obtain the pore features in the CAS. The sensitive influence of coarse aggregate morphologies on the pore features was evaluated by GA-BP neural network. Results show that air void in the skeleton is most sensitive to the composite flat-elongated index and composite sphericity of 13.2mm aggregates, and composite sphericity of 9.5mm aggregates. The composite sphericity of 13.2mm aggregates, composite flat-elongated index and composite texture index of 9.5mm aggregates, composite flat-elongated index, composite angularity index, and composite texture index of 4.75mm aggregates are the high-sensitivity influencing factors to the fractal characteristic of pore structures.

Influence of mineral filler characteristics on the filler–asphalt interfacial behavior

The knowledge of mineral filler characteristics and their impacts on filler–asphalt interfacial behavior is not systematic and completed yet. In this paper, eight mineral fillers prepared using the same milling procedure were investigated. The filler–asphalt interfacial behavior was analyzed by differential scanning calorimetric and dynamic shear rheometer tests. Results reveal that in contrast to form factor and specific surface area, particle porosity, particle density, aspect ratio, angularity index, fractal dimension and feature roughness decrease with decreasing particle size. Limestone filler exhibits more regular shape, less significant angularity and richer surface texture than basalt filler. Of all particle characteristics studied, form factor and specific surface area are suggested to be the determining factors affecting filler–asphalt interfacial behavior. Moreover, microscopic morphology analysis provides an insight to interpret the differences explored in mastic interfacial property. The results help employ applicable particle characteristics that fabricate mastic with a stable interface system.

Research on the intensity profiles of high-order Laguerre-Gaussian mode laser beams

Here we analyzed the intensity profile properties of the Laguerre-Gaussian (LG) mode laser beams, to facilitate the intracavity intensity modulation for high-order LG mode laser output. The commonly used definitions of ring-like beam size are discussed, including the second moment of light intensity, power in the bucket, and the peak intensity radius of the ring-like beam. The differences between these methods underscore the importance of selecting appropriate beam size definitions when estimating the mode order, which is particularly worthy of attention when employing certain mode-selection techniques, such as using a defect spot, an aperture, or inducing spherical aberration (SA), to achieve high-order mode outputs. In the experiment, high-order mode LG0,±m output were obtained by utilizing the SA of a short-focal lens in the cavity of an end-pumped Nd:YVO4 laser at 1064 nm. The highest angular indices m reached 355, which is the highest order of LG mode output obtained directly from a laser cavity. The experimental relationship between the mode-order and cavity parameters matched well with the theoretical results, validating the analysis of the intensity profile properties.

Study on the influence of aggregate on rheological properties of recycled aggregate asphalt mixture using microstructural quantification

Recycled aggregate (RA) is generated through the crushing process of Construction and Demolition Waste (CDW). Although there has been extensive research on the mechanical properties of recycled aggregate asphalt mixture (RAAM), the impact of recycled aggregate (RA) on its rheological characteristics remains underexplored. This paper aims to assess the rheological properties of recycled aggregate asphalt mixture (RAAM) during the processes of mixing and compaction. Firstly, different percentages of recycled aggregate (RA) were utilized in the design of the recycled aggregate asphalt mixture (RAAM), and rheological behaviors of RAAM during the mixing and compaction stage were characterized by mixing torque and compaction energy, respectively. Then, high-precision three-dimensional models of RA were reconstructed utilizing CT images, and four indices were established to quantitatively assess the macro shape and micro-morphology of RA particles, utilizing the spatial model data for precise measurements. Finally, a correlation was found between rheological properties of RAAM and RA morphology through a comprehensive analysis of laboratory test results and spatial model indicators. Results show that aggregate particles’ microstructural morphology significantly influences asphalt mixture’s rheological behavior during mixing and compaction. Additionally, the 3D spherical degree and Needle-flake index performed more significant correlations with mixing and compaction than the 3D angular index and 3D texture index. As opposed to natural aggregate, RA exhibits more intricate morphological characteristics stemming from its porous cement mortar composition. Increasing the RA content causes more energy consumption and increases the thickness of asphalt mortar film during the compaction process. In general, methods established in this study offer an efficient mean of quantifying the morphological characteristics of aggregate particles, thereby enabling the assessment of the impact of RA on the rheological properties of asphalt mixtures.

Monodisperse and polydisperse packings of equiaxed concave particles: Effects of angularity and roughness

In this study, the monodisperse and polydisperse packings with intentionally designed angularity index (AI) and roughness (RG) distributions were constructed via DEM simulations. The corresponding packing properties, such as packing density, coordination number, connectivity number and anisotropy of branch vectors were comprehensively examined. The isolated effects of AI and RG on packing properties were investigated based on simulation results of monodisperse packings. The study also explored how the polydispersity of AI and RG influences packing properties, with insights drawn from the simulation results of polydisperse packings. By analyzing variations in pore volume, the study proposed predictive models that account for the contributions of AI and RG for packing density of monodisperse packings. These models were further used as the foundation for constructing predictive models for packing density of polydisperse packings.

Evaluation of angular, linear, and body index measures of pêga donkeys (Equus Asinus) from southeast of Brazil

The objective of this study was to perform body evaluation of Pêga donkeys (40 females and 10 males) from the Southeast Region of Brazil. Hippometer, measuring tape, and arthrogoniometer were used, considering the left antimere of the animals in a forced quadrupedal position. The analysis of variance showed a difference (p<0.05) between males and females for chest width, CPr, withers height, croup height, body length, back-loin length, posterior pastern length, and the angle of the tibiometatarsal joint. The values for body length, anterior pastern length, scapulohumeral angle, and metacarpophalangeal joint differed (p<0.05) between farms. Compactness index 1 and conformation index classified the animals as suited for saddle activities, and compactness index 2 classified them as suited for light drafting. The dactylothoracic index classified the animals into eumetric. Cannon load index was similar between sexes and between states. The load on the back by step index was 167.9±12.6 kg, and the LGI was 95.9±6.0 kg, equal between sexes and higher for the animals from RJ. It is concluded that the Pêga breed has sexual dimorphism and regional selection, interfering with morphometry and aptitude for saddle and light draft.

Systematic investigation into the role of particle multi-level morphology in determining the shear behavior of granular materials via DEM simulation

This study aims to numerically investigate the dependence of shear behaviors of granular materials on particle multi-level morphology, encompassing form (mean of elongation and flatness), angularity, and roughness. To this end, four series of particles—ellipsoidal particles with varying elongation indices (EI) and flatness indices (FI), and equiaxed concave particles with varying angularity indices (AI) and roughness (RG)—are adopted to isolate the effects of particle morphology at each level. Through discrete element method (DEM) simulations, granular assemblies with varying values of EI, FI, AI, and RG are consolidated to achieve the maximum packing density under the same confining pressure. Subsequently, they are subjected to triaxial drained compression tests until reaching a critical state. Based on numerical results, the independent effects of EI, FI, AI, and RG on the macro- and micro-mechanical response of granular materials are examined and compared in detail. Furthermore, using the ‘Stress-force-fabric’ (SFF) relationship, the anisotropic origins of the peak- and critical-state shear strengths induced by EI, FI, AI, and RG are also analyzed.

Metasurface-Based Enhanced Orbital Angular Momentum Index Modulation for High Spectral Efficiency and Energy Efficiency

Metasurface-Based Enhanced Orbital Angular Momentum Index Modulation for High Spectral Efficiency and Energy Efficiency

Ectopic eruption of maxillary first permanent molars: Risk factors and association with alveolar and maxillary characteristics on children

Background/purposeThe etiology of the ectopic eruption (EE) of the maxillary first permanent molars (FPM) remains unclear and controversial. This study was designed to explore the dental and skeletal factors for EE of the FPM in children. Materials and methodsChildren aged 6–10 years were recruited to this study. Subjects were assigned to the ectopic eruption group (EEG) and the normal eruption group (NEG). Lateral cephalometric radiographs and panoramic radiographs were measured by angular and linear indices. ResultsThe prevalence of EE of maxillary FPM was higher in males and at younger ages. Subjects with skeletal class III malocclusion were more likely to be diagnosed with EE of maxillary FPM. The SNA, ANB, FMIA, Wits, Ptm-A, ANS-PNS, overbite, and overjet were significantly different between the EEG and the NEG. The length of the posterior region of the maxillary alveolar bone, U6-OP, and eruptive angulation of the maxillary FPM were statistically different between the two groups. ConclusionMale sex, skeletal class III malocclusion, mesial inclination of the maxillary FPM, hypoplasia of the maxilla, and insufficient length of the posterior region of the maxillary alveolar bone were related to EE of the maxillary FPM.

Quick extraction of recycled sand morphology parameters based on deep learning and their effect on mortar property

Due to the limited application of the natural river sand in China, recycled sand (RS) has been considered as an important replacement of natural sand in sustainable construction. The morphology of recycled sand is critical to its effective application in mortar and concrete. An environmentally friendly approach is introduced in this work to improve the morphology of recycled sand during its crushing process. This paper presents a newly developed image acquisition device, which obtained 25,328 RS images to use as a dataset for the construction of a segmentation model based on deep learning technology with an automatic segmentation of RS characteristics. Evaluation indices including accuracy (ACC), Recall, intersection over union (IoU), and F1-score index are reaching up to 99.8%, 88.1%, 84.9% and 84.3%, respectively. RS morphological characteristics including the flat and elongation ratio (FER), angularity index (AI), roundness (R) are automatically extracted by the proposed model, and the predicted results agreed well with the experimental ones. Finally, the effect of FER of RS on mortar’s mechanical properties is investigated by a series of experiments. Results reveal that the flowability, flexural strength and compressive strength of mortar decreased invariably with the lower FER of sand.

Vector vortex beams sorting of 120 modes in visible spectrum

Abstract Polarization (P), angular index (l), and radius index (p) are three independent degrees of freedom (DoFs) of vector vortex beams, which have found extensive applications in various domains. While efficient sorting of a single DoF has been achieved successfully, simultaneous sorting of all these DoFs in a compact and efficient manner remains a challenge. In this study, we propose a beam sorter that simultaneously handles all the three DoFs using a diffractive deep neural network (D2NN), and demonstrate the robust sorting of 120 Laguerre–Gaussian (LG) modes experimentally in the visible spectrum. Our proposed beam sorter underscores the considerable potential of D2NN in optical field manipulation and promises to enhance the diverse applications of vector vortex beams.

Roughness and Angularity of Fragments from Meteorite Disruption Experiments

In this study, we set out to explore the relationship between fracture roughness and sample strength. We analyze 45 fragments of Aba Panu, Allende, and Tamdakht, three meteorites that have been strength-tested to disruption, to determine whether their shape or texture is correlated with measured compressive strength. A primary goal is to understand whether these exterior properties correlate with more challenging strength-related measurements. We first scan the samples and construct high-fidelity 3D models. The gradient-based angularity index AI g and the rms slope roughness metric θ rms are applied to all nine samples, and their validity and any correlation between them are analyzed. We find that different sample subsets show significant variation in both correlation strength and direction. We also find AI g to be of questionable validity in its application to highly angular samples. Based on our methodology and results, we do not find sufficient separation between the roughness values of samples to allow distinct identification of the three meteorites based on roughness alone. Additionally, neither metric shows a strong correlation with the strength of individual fragments. We do find, however, that the spread of the fragment strength distribution within a given meteorite has some correlation with its average roughness metric. Increased fragment roughness may imply greater structural heterogeneity and therefore potentially weaker behavior at larger sizes. We only have significant data sets for two meteorites, however, which are insufficient to correlate meteorite fracture roughness to meteorite strength in any simple way.

Influence of coarse aggregate morphology on the mechanical characteristics of skeleton in porous asphalt concrete

ABSTRACT The properties of coarse aggregates have a great influence on the mechanical characteristics of porous asphalt concrete (PAC). The objective of this study is to reveal the influence of coarse aggregate morphology on the skeleton mechanical characteristics of PAC-13. To achieve this goal, a microstructure analysis method based on X-ray CT was developed to acquire three-dimensional morphological characteristics of coarse aggregates, and the morphology parameters were proposed. Based on the morphology of the actual aggregate, the coarse aggregate skeleton structure and skeleton penetration test were simulated by the discrete element method (DEM) and the values of skeleton strength under different morphologies were determined. The sensitive influences of coarse aggregate morphology parameters on the skeleton strength were quantified by the GA-BP neural network and the recommended value ranges of morphology parameters were proposed. The results show that the morphology of coarse aggregates within the size range of 4.75∼9.5mm and 9.5∼13.2mm has the greatest influence on the skeleton strength of PAC-13. The composite flat-elongated index and composite texture index of aggregates in 9.5∼13.2mm and 4.75∼9.5mm, and the composite angularity index of aggregates in 4.75∼9.5mm, which are referred to as Icom(9.5∼13.2), Icom(4.75∼9.5), Tcom(9.5∼13.2), Tcom(4.75∼9.5), AIcom(4.75∼9.5), are the high-sensitive influencing factors to the skeleton strength of PAC-13.

High angular sensitivity refractive index sensors based on 1D single-defect magneto-optical photonic crystals

Strong localization and enhancement of fields may arise in the defect layer of an 1D single-defect magneto-optical photonic crystal (1DSDMOPC), which has been applied to design and fabricate several types of optical devices. In this work, we demonstrate numerically that, for the case that a linearly polarized light is normally incident on a selected 1DSDMOPC, rotation angle induced by polar linear magneto-optical Kerr effect may strongly depend on refractive index of the fluid encountered by the transmission, which indicates that 1DSDMOPC is promising to be applied as a refractive index sensor based on Kerr angle detection. Furthermore, it is shown that sensitivity and detection range of the sensor can be adjusted by either modifying refractive index of the dielectric layers or altering number of layers of the 1DSDMOPC. An angular sensitivity in the order of 104 °/RIU is inferred, a value much larger than both the one usually encountered in photonic crystal sensors and the surface plasmon resonance based sensors (the angular sensitivity usually in the order of 101 or 102 °/RIU). Our work may provide a new possible way to design and manufacture high angular sensitivity sensors by using 1DSDMOPCs.

Image-based indices of aggregates for predicting the initial skid resistance of bituminous pavements

The objective of this study is to propose image-based indicators of microtexture and macrotexture for pavement surfaces that can predict the initial skid resistance. To achieve this objective, images of different types of aggregates that were collected from quarries were processed. Based on the outcome of the image processing, suitable indicators of shape, angularity, and surface texture of coarse aggregates were proposed. Skid resistance data were collected from pavements constructed with the aggregates used in the image processing, as well as with different surface course mixes commonly used in India, such as Bituminous Concrete (BC), Stone Matrix Asphalt (SMA), and Gap-Graded Rubberized Bituminous mix (GGRB).Through a detailed investigation of the image processing outcome and field data, this study introduces the Aggregate Surface Texture Index (STI) as a means of quantifying microtexture, which can be obtained by processing images of the aggregate using wavelet decomposition technique. Additionally, the study proposes Shape Index (SI) and Angularity Index (AI) as indicators for macrotexture, which can be obtained from the processing of digital images of aggregates. For determining the skid resistance of newly constructed pavements, the study suggests using the Surface Macrotexture Index (SMI), which can be obtained by processing digital images of the pavement surface. Furthermore, this study proposes statistical models for predicting the initial skid resistance of pavement based on these indicators. Overall, the proposed image-based indicators of microtexture and macrotexture have the potential to provide valuable insights for designing and maintaining safe and durable pavement surfaces.

Vector Angular Continuity in the Fusion of Coseismic Deformations at Multiple Optical Correlation Scales.

As one of the common techniques for measuring coseismic deformations, optical image correlation techniques are capable of overcoming the drawbacks of inadequate coherence and phase blurring which can occur in radar interferometry, as well as the problem of low spatial resolution in radar pixel offset tracking. However, the scales of the correlation window in optical image correlation techniques typically influence the results; the conventional SAR POT method faces a fundamental trade-off between the accuracy of matching and the preservation of details in the correlation window size. This study regards coseismic deformation as a two-dimensional vector, and develops a new post-processing workflow called VACI-OIC to reduce the dependence of shift estimation on the size of the correlation window. This paper takes the coseismic deformations in both the east-west and north-south directions into account at the same time, treating them as vectors, while also considering the similarity of displacement between adjacent points on the surface. Herein, the angular continuity index of the coseismic deformation vector was proposed as a more reasonable constraint condition to fuse the deformation field results obtained by optical image correlation across different correlation window. Taking the earthquake of 2021 in Maduo, China, as the study area, the deformation with the highest spatial resolution in the violent surface rupture area was determined (which could not be provided by SAR data). Compared to the results of single-scale optical correlation, the presented results were more uniform (i.e., more consistent with published results). At the same time, the proposed index also detected the strip fracture zone of the earthquake with impressive clarity.

Quantum-information theory of magnetic field influence on circular dots with different boundary conditions

Influence of the transverse uniform magnetic field B on position (subscript ρ) and momentum (γ) Shannon quantum-information entropies S ρ,γ Fisher informations I ρ,γ and informational energies O ρ,γ is studied theoretically for the 2D circular quantum dots (QDs) whose circumference supports homogeneous either Dirichlet or Neumann boundary condition (BC). Comparative analysis reveals similarities and differences of the influence on the properties of the structure of the surface interaction with the magnetic field. A conspicuous distinction between the two spectra are crossings at the increasing induction of the Neumann energies with the same radial quantum number n and adjacent non-positive angular indices m. At the growing B, either system undergoes Landau condensation when its characteristics turn into their uniform field counterparts. It is shown that for the Dirichlet system this transformation takes place at the smaller magnetic intensities; e.g. the Dirichlet sum on its approach from above to a fundamental limit is at any B smaller than the corresponding Neumann quantity what physically means that the former geometry provides more total information about the position and motion of the particle. It is pointed out that the widely accepted disequilibrium uncertainty relation , with d being a dimensionality of the system, is violated by the Neumann QD in the magnetic field. Comparison with electrostatic harmonic confinement is performed; in particular, contrary to the hard-wall QDs, for this configuration the sums S ρ + S γ and the products I ρ I γ and O ρ O γ do not depend on the field. Physical interpretation is based on the different roles of the two BCs and their interplay with the field: Dirichlet (Neumann) surface is a repulsive (attractive) interface.

Extending orbital angular momentum multiplexing to radially high orders for massive mode channels in fiber transmission.

Orbital angular momentum (OAM) beams with different angular indices l have the potential to greatly increase communication capacity. However, the finite aperture of optical systems limits the value of the angular index. In order to fully use the orthogonal mode channels supported in the fiber for high-capacity communications, we propose extending the radial indices p of OAM modes as an additional multiplexing dimension. In this paper, we introduce spatially discrete multiple phase planes to multiplex the angular and radial OAM modes simultaneously. Due to the orthogonal property of the central symmetric OAM modes, a two-dimensional (2D) input Gaussian beams array can be converted to coaxial OAM modes through Cartesian to log-polar coordinate transformation by inverse design. For a proof-of-concept demonstration, a 10-mode multiplexer for high-order radial OAM modes was designed using five phase planes. The fabricated multiplexer generated high-quality multiplexed OAM modes with a loss of less than 5.4 dB. The multiplexed OAM modes were coupled into a specially designed ring-core fiber by mode-field matching, achieving stable mode transmission in 2 km fiber. The approach provides a scalable technology to increase the number of transmission channels and could lead to the practical applications of OAM multiplexing in communication.

Three-Dimensional Angularity Characterization of Coarse Aggregates by the Optimal Ellipsoid Approximation Algorithm

The three-dimensional (3D) angularity of coarse aggregates was investigated in this study by an optimal ellipsoid approximation algorithm. The minimum volume enclosing ellipsoid (MVEE) of the 3D coarse aggregate particle represented by the surface point cloud was computed by a Python program. An algorithm was proposed to compute the optimal ellipsoid that is inscribed in the aggregate particle as far as possible. In the algorithm, a fitting index was proposed and a cycle program was coded to search the optimal ellipsoid. Based on the optimal ellipsoid and the point cloud of the coarse aggregate particle, a 3D angularity index was proposed. The critical discriminant coefficient was introduced into the angularity index to filter out the tiny convex parts on the particle. Six 3D geometric models were generated and five 3D aggregate particles were randomly selected to verify the effectiveness of the angularity index. The results demonstrate that the angularity index proposed in this study can effectively distinguish the angularity of different geometric models. The effect of mesh precision on the angularity index was analyzed and the critical discriminant coefficient was studied by the parameter analysis method and Delphi expert investigation method.