Three-dimensional Morphological Characteristics Research Articles

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.

Effectiveness of Matched and Mismatched Natural Rock Joints Using Experimental Direct Shear Tests

In practice, the shear strength of joints is not only determined by the roughness, but also by the degree of joint matching. Due to alteration or movement, the joints with equal roughness might be mismatched. The matching degree of the joint is a significant factor that controls the normal closure, aperture, stiffness, hydraulic conductivity, and shear strength of the jointed rock mass. Studying the shear behavior of natural mismatched rock joints obtained from core drilling with different morphological characteristics, degrees of matching, and irregular shapes is an issue that has gained less attention due to the lack of samples and difficulty to obtain data. This study investigates the shear behavior of mismatched joints obtained from core drilling. Here, a new criterion is developed based on 35 series of direct shear tests, Barton and other classical theories, three-dimensional morphological characteristics, and matching condition of joints. To validate the proposed criterion, the estimation accuracy of the available classical models is compared with that of the new model. It is observed that the new criterion could achieve higher prediction accuracy for mismatched joints. Moreover, it is found that the average estimation error of the predicted values is reduced by considering the matching conditions.

Mapping three-dimensional morphological characteristics of tidal salt-marsh channels using UAV structure-from-motion photogrammetry

Tidal channels (TCs) are geomorphological features of coastal and tidal landscapes. They provide a pathway for the exchange of material and energy between marshes and adjacent water bodies and thereby control the hydrodynamic, morphological, and ecological processes on marsh platforms. Due to difficulties in terms of accessibility, limitations on the duration of exposure during low-water stages, and variations in morphology over time, rapid and accurate mapping of such intertidal morphological features at a high frequency is extremely challenging. Here, we present an efficient method integrated unmanned aerial vehicles (UAVs) structure-from-motion (SfM) photogrammetry, and spatial morphological fitting and delineation for accurately quantifying channel three-dimensional (3D) morphological features in terms width, depth, width-to-depth ratio, and cross-sectional area. We also relate these measured proxies to salt marsh species distributions. A two-step thresholding approach combining elevation and slope is developed in order to determinate TC boundaries from salt marsh and tidal flat area, and a Gaussian fit is used to estimate water-bearing channel depth and cross-sectional area. Salt marsh species are identified from fine-resolution multispectral satellite data and a field training dataset using a Random Forest classifier. Our results indicate that (1) UAV-based SfM photogrammetry can achieve centimeter-level accuracy in mapping the topography of TCs, with a root mean square error (RMSE) of 5.7 cm — mainly from the strong reflection of light from smooth TC water surfaces and the presence of water-bearing layers; (2) the morphological features of TCs, ranging from tidal flats to salt marsh areas, demonstrate a similar tendency, which increases at first and then decreases. The maximum depth and cross-sectional area of TCs is in sparse salt-marsh area, up to 4 m and 150 m2, respectively; and (3) TC morphology has a major impact on the distribution of salt marsh plants and such effects vary across different plant species. These results greatly contribute deep understanding of feedbacks between TCs and salt marsh plant species distribution and have significant implications for developing ecological and morphological salt marsh restoration guidelines.

Research on Three-Dimensional Morphological Characteristics Evaluation Method and Processing Quality of Coarse Aggregate

The size, shape, gradation and appearance of aggregate have a significant impact on the road performance of asphalt mixtures, which is directly related to the deformation characteristics and fatigue resistance of asphalt mixtures. In order to be able to design a long-life asphalt pavement, the aggregate must have reasonable morphology and morphological characteristics. In order to quantitatively analyze the shape characteristics of the road coarse aggregate, a high-precision three-dimensional scanner is used to obtain the characteristic lattice of the aggregate surface, and the solid model of the coarse aggregate particles is established. The two-dimensional and three-dimensional morphological indicators of the aggregate are analyzed and discussed. Meanwhile, aggregates processed by typical quarries in Guangdong Province are collected, and the influence of different processing techniques on the morphology of aggregates are analyzed. The results show that the difference between the perimeter and projected area of the aggregate contour under different viewing angles is relatively large, which is closely related to the flatness index of the aggregate. It can better characterize the three-dimensional shape of the aggregate. The closer the aggregate is to the cubic state, the greater the sphericity value; the ellipsoid index calculated based on the three-dimensional circumscribed ellipsoid can better characterize the angularity of the aggregate. The worse the angularity of the aggregate, the larger the corresponding ellipsoid value. The sphericity of the aggregate processed by counter-breaking is lower, and the angularity is better. The sphericity of the aggregate processed by the shaping process is the best, but the angularity is lower. According to actual needs, different processing techniques can be combined and blended to obtain aggregate finished products with a more balanced grain shape and angularity. The richer the angularity of the coarse aggregate, the better the high-temperature stability and fatigue resistance of the asphalt mixture. However, the stability of performance indicators will become worse. In practical engineering applications, it is recommended to further combine the screening efficiency of the hot material screen of the mixing plant with the stability of the hot material gradation and the uniformity of construction quality to select a suitable aggregate processing technology.

Effects of Induction Culture on Osteogenesis of Scaffold-Free Engineered Tissue for Bone Regeneration Applications.

Restoration of the bone defects caused by infection or disease remains a challenge in orthopedic surgery. In recent studies, scaffold-free engineered tissue with a self-secreted extracellular matrix has been proposed as an alternative strategy for tissue regeneration and reconstruction. Our study aimed to engineer and fabricate self-assembled osteogenic and scaffold-free tissue for bone regeneration. Osteogenic scaffold-free tissue was engineered and fabricated using fetal cartilage-derived progenitor cells, which are capable of osteogenic differentiation. They were cultured in osteogenic induction environments or using demineralized bone powder for differentiation. The fabricated tissue was subjected to real-time qPCR, biochemical, and histological analyses to estimate the degree of in vitro osteogenic differentiation. To demonstrate bone formation in an in vivo environment, scaffold-free tissue was transplanted into the dorsal subcutaneous site of nude mice. Bone development was monitored postoperatively over 8weeks by the observation of calcium deposition in the matrix. In the in vitro experiments, engineered osteogenically induced scaffold-free tissue demonstrated three-dimensional morphological characteristics, and sufficient osteogenic differentiation was confirmed through the quantification of specific osteogenic gene markers expressed and calcium accumulation within the matrix. Following the evaluation of differentiation efficacy, in vivo experiments revealed distinct bone formation, and that blood vessels had penetrated the fabricated tissue. The novel engineering of scaffold-free tissue with osteogenic potential can be used as an optimal bone graft substitute for bone regeneration.

Analysis of Reservoir Seismic Law Based on Three-Dimensional Morphological Characteristics of Joint Surface Related to Listric Fault

Since water storage, earthquakes occurred in Badong County, Hubei Province, accounted for as much as one-third of the strong earthquakes in the Three Gorges Reservoir area. For example, the MS5.1 earthquake occurred in December 2013 near the Gaoqiao fault in Badong County. The earthquake time, magnitude, and location analysis showed that reservoir earthquakes in this area exhibited some characteristics, such as periodicity, migration, and deep extension. Based on the regional stratum lithology and structural characteristics, this paper designed a curved joint on a small scale to simulate the structural morphology of the Gaoqiao fault and carried out triaxial compression tests under different immersion times to analyze the morphological parameters of the joint surface. The results showed that topological parameters such as root mean square height (Sq), arithmetic average height (Sa), reverse load area ratio (Smc), and minimum autocorrelation length (Sal) could effectively characterize the degree of damage and deterioration of curved joints. The test privides a reference for analyzing the evolution law of the seismic characteristics of the reservoir.

Mechanical Response of Listric Faults in the Three Gorges Reservoir Area Based on Three-Dimensional Morphological Characteristics

Faults or joints widely exist in rock masses, which deeply affect the mechanical properties of rock. The seismic frequency of the Gaoqiao fault and its surrounding areas in the Three Gorges Reservoir area before and after water storage is significantly higher than that in other areas. In this study, a curved joint is used to simulate the occurrence characteristics of the Gaoqiao fault, and the influence of reservoir water is simulated by adjusting the fracture water pressure. Compared with the changes of joint surface morphology parameters before and after the test, it is found that the macro failure characteristics of rock samples are in good agreement with the micromorphology changes of the joint surface. Among them, the parameters such as root-mean-square height (Sq), arithmetic mean height (Sa), reverse load area ratio (Smc), and minimum autocorrelation length (Sal) can better characterize the joint surface deterioration of rock samples under the action of fracture water pressure. The test results have a certain reference value for studying the fault response under the action of reservoir water.

Studying a Long-Lasting Meteor Trail from Stereo Images and Radar Data

Unique observation of a long-lasting meteor trail of about half an hour duration is described. The trail resulted from a burning meteor from the Leonid storm flux in the middle latitudes over eastern Siberia. We describe three-dimensional morphological characteristics of both the meteor and the long-lasting trail using data from wide-angle CCD cameras. Additionally, we present the meteor and the trail radiolocation characteristics obtained with a meteor radar and ionosonde. The background dynamics of the upper atmosphere at the height where the long-lasting trail developed were observed using data from the meteor radar and Fabry-Perot interferometer. The obtained results allowed the conclusion that the dynamics of a long-lasting trail are conditioned by the wind. However, during the first minutes of trail development, it is possible that a high-speed component is present, resulting from explosion of the meteor body in the atmosphere. A primitive spectral analysis of the long-lasting trail’s optical emissions and earlier studies point to hydroxyl molecules as a possible source of the glow. We believe the enhanced hydroxyl emission could be related to interaction of excited O(1D) oxygen atoms with meteor body water in the Earth’s upper atmosphere.

Process maps and optimal processing windows based on three-dimensional morphological characteristics in laser directed energy deposition of Ni-based alloy

Constructing processing window to fabricate defect-free components with high forming quality and desired performance has been crucial in directed energy deposition. Due to its complexity as a mass and energy time-dependent system, it is still a key problem to be solved for laser powder-fed additive manufacturing to choose opportune processing parameters. In this paper, single scan track experiments were conducted under various combinations of processing parameters including laser power, scanning speed and powder feeding rate. Scan tracks had been thoroughly investigated through three-dimensional information including surface, longitudinal section and transverse section, which were correlated to each other in showing track morphological characteristics in directed energy deposition. Surface ripples, resembling fish scale in welding and chevron in selective laser melting, were found in directed energy deposition under low powder feeding rate and high linear energy density. Furthermore, several quantitative indexes, which were dimensionless mean roughness and ripples’ interval in surface, dimensional roughness in longitudinal section and dilution rate in transverse section, were used to evaluate the forming quality. These quantitative indexes were found to be closely related to the defects in additive manufacturing, and forming quality and accuracy of additive-manufactured components. Relationship between proposed indexes and processing parameters was studied and the mechanism behind it was also discussed. Five states which were no fusion, lack of fusion, optimum, rough surface and undesired dilution rate were distinguished based on the proposed quantitative indexes. Finally, a processing window based on these indexes was proposed for the laser powder-fed additive manufacturing for Inconel alloys. It is found that powder feeding rate affects the distribution of the five states and laser power, scanning speed affect the range of the five states.

Three-dimensional morphological characteristics of particles in nature and its application for DEM simulation

The particle's shape is one of the important factors affecting the physical and mechanical behaviors of granular materials. To study the morphological characteristics, the 3D point cloud of the surface of three kinds of particles in relation to different formations (including large scale rock blocks formed by two landslides, artificial crushed rock blocks and little sand particles) with different sizes in nature are obtained by using laser scanning and computed tomography (CT). Subsequently, a reconstruction method based on a spherical harmonic function is provided to automatically and accurately reconstruct the 3D model of each particle based on the point cloud of their surfaces. From this, a database of each particle's 3D model has been built, and of which six morphological parameters of the particles are statistically analyzed. The correlation between these parameters are studied, which proved a strong linear correlation between VESD-V/S, S-Cx and S-SR of any kind of particle. The results show that the particle's formation will have a great influence on the particle's shape, and a multi-factor “DNA” series of particles have been suggested, such as VESD-S-R, or VESD-Cx (SR) -R, or V/S-S-R, or V/S-Cx (SR) -R. Finally, discrete element method (DEM) is used to study the influence of the representing accuracy of the particles' model on the numerical results, which shows that considering the simulation effect and calculation efficiency, the face number value with surface area error lower than 15% are well for characterizing the model of the particles.

Morphological Changes of Collagen Fibers in Myocardium of Rats under Different Exercise Loads Based on Three-Dimensional Simulation Technique.

In order to improve the visual analysis ability of the morphological changes of rat liulimyocardial collagen fibers under different exercise loads, a method of extracting the morphological changes of collagen fibers in rat myocardium under different exercise loads based on three-dimensional simulation technique is proposed. The three-dimensional morphological characteristics of the collagen fibers in the original rat myocardium are made by CT scanning technique. Like information collection, a gradient decomposition method is used to filter the three-dimensional morphological features of rat myocardial collagen fibers. The edge contour features of the three-dimensional morphological features of rat myocardial collagen fibers under different motion loads are extracted. The threshold segmentation method is used to carry out the rat myocardial glue under different exercise loads. The segmentation of the regional pixel feature block of the three-dimensional morphological features of the original fiber is segmented into a block vector with high resolution, and the regional reconstruction of the three-dimensional morphological features of the rat myocardial collagen fibers under different motion loads is carried out to realize the high resolution identification and classification of the 3D morphological features of the rat myocardial collagen fibers. The simulation results show that the three-dimensional simulation of the morphological changes of rat myocardial collagen fibers under different exercise loads is better, and the accuracy of feature extraction is higher.

Three-dimensional Morphological Characteristics of Barchan Dunes Based on Photogrammetry with A Multi-rotor UAV

Three-dimensional Morphological Characteristics of Barchan Dunes Based on Photogrammetry with A Multi-rotor UAV

Three-Dimensional Morphological Characteristics of Lower Lumbar Intervertebral Foramen with Age.

Intervertebral foramen is the doorway of nerve root and it plays an important role of radiculopathy and surgical treatment of intervertebral foramen diseases. The purpose of the study is to obtain three-dimensional (3D) morphological characteristics of lumbar intervertebral foramen and their relationship with age. Pedicle-superior articular process (P-SAP), disc height between adjacent vertebra (DH), pedicle-inferior vertebrae (P-IV), inferior posterior vertebrae-superior articular process (IPV-SAP), and bony boundary area (BBA) were measured in entrance, middle slice, and exit of lumbar intervertebral foramen for 25 males of different age groups. Spinous process to intervertebral foramen entrance (SP-IFE) was measured for 25 males of different age groups. Overall, P-SAP and P-IV decreased and IPV-SAP increased from the entrance to the exit of intervertebral foramen for L3/4-L5S1. DH decreased at entrance slice, middle slice, and exit slice for L3/4-L5S1 with age. Significant difference with aging was found only at the middle slice of L3/4 and L4/5 for P-SAP. And the significant decrease of IPV-SAP was observed at middle slice of L3/4, entrance slice of L4/5 and L5S1, and exit slice of L5S1. SP-IFE is not consistent for all subjects. In addition, the decrease of BBA at L3/4 and L4/5 was observed earlier than at L5S1. The present study described detailed information of intervertebral foramen, which may be of benefit for better understanding of the pathology and surgical planning for intervertebral foramen diseases.

Three-Dimensional Morphological Characteristics Measurement of the Hip Based on Computed Tomography Image Post-Processing

Three-Dimensional Morphological Characteristics Measurement of the Hip Based on Computed Tomography Image Post-Processing

Morphological study of tibial plateau based on three-dimensional computed tomography image and its clinical significance

Objective To investigate the three-dimensional morphological characteristics of tibial plateau based on CT image post-processing technique and analyze its significance in preoperative planning of tibial plateau fractures. Methods Multi-slice spiral CT data of 98 humans (56 males and 42 females) with normal tibial plateau and 30 patients (15 males and 15 females) with tibial plateau fractures were extracted. Morphological measurements of the tibial plateau were achieved by means of a three-dimensional measurement method based on points, lines and surfaces. Differences in three-dimensional parameters between genders in normal tibial plateau and differences between normal tibial plateau and tibial plateau fractures were analyzed. Results Differences of males and females were significant in width of tibial plateau [(73.2±3.7)mm, (65.5±3.7)mm], anteroposterior dimension of medial tibial plateau [(39.8±3.5)mm, (34.8±2.6)mm] and anteroposterior dimension of lateral tibial plateau [(34.0±3.3)mm, (29.8±3 5)mm] (P 0.05). Above parameters in three-dimensional morphological measurements of tibibial plateau fractures varied compared to the normal reference value (P<0.05). Intraclass correlation coefficient (ICC) for intra-observe and inter-observer agreement in normal tibial plateau measurement was excellent. Conclusions Present research provides a series of scientific and objective data for preoperative planning of tibial plateau fractures. Measurements of tibial plateau can assist the evaluation of reduction of tibial plateau fractures. Key words: Anthropometry; Tibia; Imaging, three-dimensional; Tomography, X-ray

Three-dimensional spatial pattern of Populus euphratica nebkhas in the sparsely forested sandy land on the west of the Hotan River

A Populus euphratica nebkha is a type of wind-accumulated landform. In arid desert areas, when the wind-sand flow is blocked by P. euphratica, sand materials accumulate under and around trees. West of the Hotan River, P. euphratica is widely distributed in the sparsely forested sandy land to the south of Mazartag Mountain. The P. euphratica nebkha geomorphology is formed by wind erosion of sand and has rarely been studied. Based on a field investigation using real-time kinematics (RTK), the three-dimensional morphological characteristics and spatial distribution of the Populus euphratica nebkhas at 10 plots west of the Hotan River were quantitatively analyzed based on GIS data and statistical methods. The results were as follows. 1) The nebkhas exhibited an irregular contour with significant spatial differences in morphological parameters. Most nebkhas were in the developmental stage. 2) All nebkhas exhibited a patchy distribution, and at the patch level, P. euphratica nebkhas were dispersed throughout the study area and distributed on slopes ranging from 20° to 40°. 3) P. euphratica nebkhas were mainly distributed in the southwestern portions of the study area and on both sides of the old watercourse.

Measurement of three‐dimensional morphological characteristics of the calcaneus using CT image post‐processing

BackgroundAlthough computed tomography (CT) with three-dimensional (3D) rendering of the calcaneus is used for diagnostic evaluation of disorders, morphological measurements for the calcaneus are mostly based on a two-dimensional plane. The purposes of this study were to design a method for 3D morphological measurements of the normal calcaneus based on CT post-processing techniques, to measure morphological parameters in the male and female groups and describe gender differences of the parameters, and to investigate the reliability of such measurements.MethodsOne hundred and seventy-nine patients (83 men and 96 women) with a mean age of 40.6 (range, 21 to 59) years who underwent CT scans for their feet were reviewed retrospectively. The 3D structure of a normal calcaneus after shaded surface display reconstruction was extracted by interactive and automatic segmentation. Morphological measurements were achieved by means of a 3D measurement method based on CT image post-processing. Lengths and heights of the main parts of the calcaneus, Gissane’s angle, Böhler’s angle and the area of articular facet were worked out in 3D space. Gender-related size differences of parameters were compared using analysis of covariance (ANCOVA), adjusting for body height. Intra-observer and inter-observer reliabilities were assessed using intraclass correlation coefficients (ICCs) and the root mean square standard deviation (RMS-SD) for precision study.ResultsA large range of measurement values was found. Only the length of the anterior process was without gender difference (p > 0.05). The other parameters in the male group were greater than those in the female group (p < 0.01 for each, ANCOVA). All parameters had excellent reliability and reproducibility (ICC > 0.8). Precision was acceptable for intra-observer RMS-SD (linear, angular and areal measurements no more than 0.6 mm, 1.2° and 0.25 mm2, respectively). Inter-observer RMS-SD ranged from 0.4 to 1.6 mm for linear measurements, 1.2 to 2.5° for angles and 0.24 to 0.40 mm2 for areas.ConclusionsThree-dimensional morphological measurement based on a CT post-processing technique was highly reliable and repeatable for calcaneal anatomic morphological measurement. The current data will be helpful for anatomic reduction of calcaneal fractures and calcaneal malunion.

Morphologic characteristics of the dentition and palate in cases of skeletal asymmetry.

The purpose of this study was to clarify the three-dimensional morphological characteristics of the dentition and palate in skeletal asymmetry in patients with skeletal Class III malocclusion using a newly defined palatal reference plane in a dental cast. Twenty patients (5 males and 15 females) who had skeletal Class III malocclusion with facial asymmetry were selected. Pretreatment posteroanterior cephalometric radiographs and maxillary dental casts were used. The lateral deviation of Me was measured as the distance from a line perpendicular to Lo-Lo' that passed through CG. The angle between the Lo-Lo' plane and the J-J' plane was measured. Each maxillary dental cast was measured using a three-dimensional surface-scanning system, and the newly defined palatal reference plane was calculated. The right/left difference in the radius of curvature of the palate and right/left differences in the vertical and mesiodistal positions of the first molars were analyzed. Linear correlation and regression techniques were used. Our findings demonstrate that the lateral deviation of the mandible is closely related to the morphology of the alveolar process and to the vertical height of the dentition. In this study, the three-dimensional application of a new palatal reference plane is very useful in morphological research, and the results provide detailed information on the characteristics of facial asymmetry.

Morphological characteristics of the bony birth canal in patients with developmental dysplasia of the hip (DDH): investigation by three-dimensional CT

We investigated the three-dimensional morphological characteristics of the pelvis in adult female patients with developmental dysplasia of the hip (DDH), using computerized tomography (CT) images. Forty-two subjects with normal hips and 40 DDH patients were recruited for the study. In the DDH group, the average transverse diameter of the pelvic inlet was significantly less and the average transverse diameter of the pelvic outlet was significantly greater than the measurements in the normal group. Further, the bony birth canal in DDH patients exhibited a higher incidence of anthropoid-type geometry, as defined by a longer sagittal diameter relative to the transverse diameter of the pelvic inlet. These findings indicate a characteristic pelvic geometry and suggest different development of the pelvis in the transverse direction in DDH patients. In addition, the obstetric conjugate length/transverse diameter of the pelvic inlet ratio was correlated to the degree of severity of acetabular dysplasia. This finding suggests that DDH is a manifestation of a developmental characteristic of the pelvis.

Analysis of foot shape variation based on the medial axis of foot outline

The variations in foot outline forms are analyzed by using flexion angles of the medial axis of foot outline. Foot outline and 12 conventional measurements taken on the right foot of 443 male and 297 female subjects with no visible pathological deformation of the foot were used for analyses. The results indicate that the foot is outflared in most of the subjects. Medial bulge and lateral concavity of foot outline are responsible for the foot outflare, and they are not correlated with each other. Medial bulge is due to the overhang of navicular bone that is caused by the pronation of the foot. Its intensity is negatively correlated with dorsal arch height. Lateral concavity is partly due to the abduction of talus and calcaneus relative to the tarsometatarsal bones anterior to them. These three-dimensional morphological characteristics of outflared feet intimately relate to the fit and comfort of the shoe. The flexion angles of medial axis of foot outline provide a useful tool in morphological analysis of the foot for the following reasons; (1) they carry the information on the three-dimensional foot shape that cannot be represented by conventional measurements; and (2) the data is easily obtained and calculations are easily made with minimum expense.