Three-dimensional Analytical Model Research Articles

A Parameter-Driven Methodology of Wheel Flat Modeling for Wheel–Rail Impact Dynamics

A wheel flat is a typical wheel defect that significantly impacts the wheel–rail system, posing substantial challenges to vehicle operation safety. In the existing literature, the wheel flat plane model does not account for the contribution of the width direction to the impact response and thus cannot accurately reveal the wheel–rail contact state with a flat. This paper systematically proposes a three-dimensional analytical model that considers multiple worn stages and constructs a spatial complex surface reconstruction model for flats based on NURBS technology. A vehicle–track coupled dynamics model, considering the geometry of the flat, is established to investigate the effects of flat geometry on the wheel–rail impact response and contact relationship in detail. The results show that in the subcritical regime, the wear degree of the flat predominantly affects the impact force, while in the transcritical regime, both the wear degree and velocity together determine the magnitude of the wheel–rail impact force. As the wear degree increases, the moment of wheel lateral jump occurs earlier. The spatial modeling method for flats proposed in this paper offers a novel technical approach for accurately simulating the dynamic behavior of wheel–rail contact when a flat is present.

A Parameter-Driven Methodology of Wheel Flat Modeling for Wheel–Rail Impact Dynamics

A wheel flat is a typical wheel defect that significantly impacts the wheel–rail system, posing substantial challenges to vehicle operation safety. In the existing literature, the wheel flat plane model does not account for the contribution of the width direction to the impact response and thus cannot accurately reveal the wheel–rail contact state with a flat. This paper systematically proposes a three-dimensional analytical model that considers multiple worn stages and constructs a spatial complex surface reconstruction model for flats based on NURBS technology. A vehicle–track coupled dynamics model, considering the geometry of the flat, is established to investigate the effects of flat geometry on the wheel–rail impact response and contact relationship in detail. The results show that in the subcritical regime, the wear degree of the flat predominantly affects the impact force, while in the transcritical regime, both the wear degree and velocity together determine the magnitude of the wheel–rail impact force. As the wear degree increases, the moment of wheel lateral jump occurs earlier. The spatial modeling method for flats proposed in this paper offers a novel technical approach for accurately simulating the dynamic behavior of wheel–rail contact when a flat is present.

Comparative analysis of Three-Dimensional and Two-Dimensional models for predicting the malignancy probability of subsolid nodules

IntroductionTo construct Three-Dimensional (3D) and Two-Dimensional (2D) models to predict the malignancy probability of subsolid nodules (SSNs) and compare their effectiveness. Materials and MethodsA total of 371 SSNs from 332 patients, collected between January 2020 and January 2024, were included in the study. The SSNs were divided into a training set for constructing the models and a test set for validating the models. Models were developed using binary logistic backward regression, based on factors that showed significant differences in univariate analyses. The performance of the models was assessed using the area under the curve (AUC) of the receiver operating characteristic (ROC). The AUCs of different models were compared using the DeLong test. ResultsThe AUCs for the two 3D models, one 2D model, and the Brock model were 0.785 (0.733-0.836), 0.776 (0.723-0.829), 0.764 (0.710-0.818), and 0.738 (0.679-0.798) in the training set. In the test set, these AUCs were 0.817 (0.706-0.928), 0.796 (0.679-0.913), 0.771 (0.647-0.895), and 0.790 (0.678-0.903). The two 3D models demonstrated statistically significant differences from the Brock model in the training set (P=0.024 and P=0.046). None of the four models showed significant differences in the test set (all P>0.05). ConclusionThe 3D models outperform both the 2D model and the Brock model in predicting the malignancy probability of SSNs, and the 3D model incorporating volume, mean CT attenuation value, and lobulation as factors performed the best.

Comparative analysis of Three-Dimensional and Two-Dimensional models for predicting the malignancy probability of subsolid nodules

IntroductionTo construct Three-Dimensional (3D) and Two-Dimensional (2D) models to predict the malignancy probability of subsolid nodules (SSNs) and compare their effectiveness. Materials and MethodsA total of 371 SSNs from 332 patients, collected between January 2020 and January 2024, were included in the study. The SSNs were divided into a training set for constructing the models and a test set for validating the models. Models were developed using binary logistic backward regression, based on factors that showed significant differences in univariate analyses. The performance of the models was assessed using the area under the curve (AUC) of the receiver operating characteristic (ROC). The AUCs of different models were compared using the DeLong test. ResultsThe AUCs for the two 3D models, one 2D model, and the Brock model were 0.785 (0.733-0.836), 0.776 (0.723-0.829), 0.764 (0.710-0.818), and 0.738 (0.679-0.798) in the training set. In the test set, these AUCs were 0.817 (0.706-0.928), 0.796 (0.679-0.913), 0.771 (0.647-0.895), and 0.790 (0.678-0.903). The two 3D models demonstrated statistically significant differences from the Brock model in the training set (P=0.024 and P=0.046). None of the four models showed significant differences in the test set (all P>0.05). ConclusionThe 3D models outperform both the 2D model and the Brock model in predicting the malignancy probability of SSNs, and the 3D model incorporating volume, mean CT attenuation value, and lobulation as factors performed the best.

Effects of translaminar edge crack and fiber angle on fracture toughness and crack propagation behaviors of laminated carbon fiber composites

Abstract In this study, the translaminar fracture toughness of carbon fiber laminated composites with different layer sequences was investigated experimentally and numerically for different crack directions. In the numerical study, first of all, the critical stress intensity factor was determined by using the M-integral method. Three-dimensional model and M-integral analysis were achieved in the ANSYS finite element package program. The non-local stress fracture criterion was used to in order to find failure curves of the materials. Then, in order to find the crack propagation directions numerically, the solid model was transferred to the LS-DYNA program and progressive failure analysis was performed. Fracture toughness decreased by 9.92 % with the change of crack angle from 15° to 90°. As the fiber angle changed from 0° to 45°, it decreased by 9.17 %. The biggest error between the experimental and numerical study results was found at α = 45°, with a rate of 12.3 %.

Research on the Correction of Soil Pressure Distribution Pattern in Circular Working Wells in Soft Soil Areas

This paper investigates the distribution characteristics of earth pressure on circular caisson foundations in soft soil areas based on practical engineering considerations. Utilizing a three-dimensional numerical analysis model and a displacement-based method for earth pressure calculation, the lateral earth pressure on the retaining structure is examined. Adjustments are made to the distribution pattern of earth pressure on circular caisson foundations in soft soil areas. The study demonstrates that the radius of the caisson significantly influences the spatial distribution of soil pressure. Additionally, empirical formulas for the depth and radius of the reduction in soil pressure around circular caisson foundations are obtained through the research. Comparative analysis reveals that the modified earth pressure planar foundation beam method, which accounts for the arching effect, is simpler, features more mature parameter selection, and is more cost-effective than the three-dimensional finite element method. In comparison to the standard planar elastic foundation beam method for earth pressure, it aligns more closely with the actual direction of displacement.

A UDP-glycosyltransferase gene PcUGT202A9 was associated with abamectin resistance in Panonychus citri (McGregor)

Panonychus citri (McGregor) strains have developed a high level of resistance to abamectin, but the underlying molecular mechanism is unknown. Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are critical for the removal of a variety of exogenous and endogenous substances. In this study, an enzyme activity assay revealed that UGTs potentially contribute to P. citri abamectin resistance. Spatiotemporal expression profiles showed that only PcUGT202A9 was significantly overexpressed in the abamectin-resistant strain (AbR) at all developmental stages. Moreover, UGT activity decreased significantly, whereas abamectin susceptibility increased significantly, in AbR after PcUGT202A9 was silenced. Three-dimensional modeling and molecular docking analyses revealed that PcUGT202A9 can bind stably to abamectin. Recombinant PcUGT202A9 activity was detected when α-naphthol was used, but the enzymatic activity was inhibited by abamectin (50 % inhibitory concentration: 803.3 ± 14.20 μmol/L). High-performance liquid chromatography and mass spectrometry analyses indicated that recombinant PcUGT202A9 can effectively degrade abamectin and catalyze the conjugation of UDP-glucose to abamectin. These results imply PcUGT202A9 contributes to P. citri abamectin resistance.

English-medium instruction for sale: The multimodal discourse of self-perception on Japanese liberal arts faculty websites

This study both contributes to and updates the growing body of literature into the framing of English-medium instruction on institutional websites. A three-dimensional discourse analysis model is used to investigate the self-perception of three well-established liberal arts faculties in Japan. The analysis reveals distinct features in the self-perception of these universities and teases out the ingrained ideological standpoints. Firstly, the neoliberal ideological hegemony found in other university studies exists, but Japanese universities frame it differently: the explicit focus is on profit for society rather than individual gain. Secondly, there is consensus among the institutions regarding the production of ‘globalised’ individuals, but the universities are less than definitive on what the key competencies entail, or how they are applied and measured. Finally, the study underscores the explicit alignment of institutional goals with national policy objectives, reflecting the values advocated by the Japanese education ministry. As the government’s Top Global University Project approaches its conclusion, this research provides valuable insights for Japanese universities to reassess the aims and objectives of their English-language programs. By offering a nuanced understanding of institutional discourse, this study furthermore contributes to the broader literature on EMI practices and policies, guiding future developments in Japanese higher education.

Study on Flow Characteristics of Integrated Natural Circulation Reactor Under Inclined Conditions

In order to study the flow characteristics of an integrated natural circulation reactor under inclined conditions, a typical three-dimensional analysis model of natural circulation was established. The natural circulation under inclined conditions was numerically simulated using the computational fluid dynamics method, and the velocity and temperature distribution characteristics of heat exchangers and mixed-flow channels with different inclined angles were analyzed. The results show that as the inclination angle of the heat exchanger flow rate increases, there is a spatial migration phenomenon corresponding to the direction of the average flow rate. A large inclination angle will lead to a serious deterioration of the natural circulation capacity in the lower channel. Under inclined conditions, there is a phenomenon of temperature stratification in the mixed-flow channel.

Transient Mechanism Analysis of Three-Dimensional Zinc-Nickel Single Flow Battery Based on Different Negative Electrode Structures

On the basis of the mass, momentum, charge conservation equations, in addition to coupled with the global reaction kinetic equations, a transient three-dimensional mechanistic analytical model of zinc-nickel single flow batteries (ZNBs), which comprehensively takes into account the hydrogen and oxygen evolution side reactions, the polarization distribution, as well as the structural effects of the pole lugs, is developed in this paper. After grid independence validation and experimental verification, the polarization distribution, side-reaction current density, and battery efficiency of ZNBs at high current density and multiple cycles of charging and discharging were comparatively analyzed based on this model with different anode materials of nickel sheet (NS) and porous nickel foam (NF). Subsequently, the effects of changes in negative electrode porous nickel foam thickness and porosity on battery polarization, side-reaction current density and battery efficiency were further investigated. Finally, the performance of the battery under the optimal battery state was studied. The results showed that the NF negative electrode effectively reduced the battery polarization, suppressed the battery side reactions as well as improved the battery efficiency under high current density and multiple cycles of charging and discharging, which improved the efficiency and stability of the battery.

A three-dimensional numerical well-test model for pressure transient analysis in fractured horizontal wells with secondary fractures

During oil and gas reservoir development, multi-stage horizontal wells (MFHWs) and hydraulic fracturing techniques can effectively increase estimated ultimate recovery. However, there still lacks an understanding of the three-dimensional (3D) pressure transient behaviors of multi-stage fractured horizontal wells with secondary fractures. To narrow this gap, a three-dimensional numerical well-test model based on a discrete fracture model and unstructured tetrahedral grids is developed to study the pressure transient behaviors of MFHWs with secondary fractures. The pressure transient solutions of MFHWs with secondary fractures have been demonstrated by model verifications. The results show that the proposed model can accurately capture the complex transient flow around fractures, including early radial flow that is not easily captured by two-dimensional numerical well test models. The proposed model classifies the flow regimes of a MFHW as: wellbore storage and skin effects, early radial flow, bilinear flow, linear flow, elliptical flow, pseudo radial flow, and pseudo-boundary dominated flow. It is found that the fracture geometry has a relatively large effect on the shape of the pressure derivative curve in this work. The hydraulic fracture half-length has the greatest impact on the pressure transient behaviors of the MFHW, followed by fracture height and secondary fracture half-length, as found in this study. Additionally, fracture parameters are evaluated, and actual well testing data are interpreted, taking into account the fracture height. This work is meaningful to understand the three-dimensional pressure transient behaviors of MFHWs with secondary fractures.

Research on the Calculation Method for the Load Distribution of the Dual-Input Counter-Rotating Transmission System

In order to solve the problem of an uneven load distribution in a double-input and double-output gearbox, based on the small-displacement Jacobi spin theory and considering the manufacturing and assembly errors of the gearbox, a Jacobi spin analysis model of the gearbox was established. In order to improve the accuracy of the three-dimensional tolerance analysis of the gearbox, on the basis of the processing method of parallel chain of gears and shafts and box and shafts, the serialization method of parallel chain of meshing gear pairs is proposed, and the gearbox was established. For the three-dimensional tolerance analysis model, three-dimensional tolerance analysis was carried out on the side-clearance dimensions of double-input and double-output gearboxes, and the side clearance values under the extreme value method and Monte Carlo method were deduced and combined with the theoretical side clearance to obtain the range of the side clearance of the gearboxes. Elastic deflection analysis was carried out on the gearbox shaft system, and the compensation relationship between the elastic deflection and the side clearance was investigated, so as to calculate the range of the value of the gearbox uniform load coefficient from 1 to 1.259. The error between the theoretically calculated uniform load coefficient and the experimentally tested uniform load coefficient was 6.61%, which verifies the reasonableness of the load distribution method of double-input and double-output gearboxes calculated using three-dimensional tolerance analysis combined with the elastic deflection angle, and provides a theoretical basis for the optimal design of the uniform load of multi-branch input gearboxes.

Enhancing the performance of thermoelectric generators using novel segmental arrangement of multi-functional gradient materials

Enhancing the performance of thermoelectric generators at wide range of operating temperatures is of great importance to maximize the output power. Thus, different updated semiconductor materials with different values of figure of merit are used. Accordingly, a modified design of the TEG system based on the multi-functional gradient (MFG) technique is developed. A comprehensive three-dimensional modeling and optimization analysis was developed and numerically simulated. The numerical predicted results were validated using the available measurements and numerical data. The results showed that when compared to low operating temperature semiconductor material of traditional (Bi2Te3) at a hot side temperature equals 227 °C, the updated material improved the output power and efficiency by 18.8% and 58%, respectively. At high operating temperature at Th = 620 °C, the upgraded material outperformed the Silicon–germanium (SiGeT) traditional semiconductor material by about 71% in the output power and 100% in the efficiency. Using the MFG-TEG, the performance improvement over the conventional design at Tc = 27 °C, and Th of 477 °C was around 315% for output power and 503% for efficiency. The current findings introduce a brand-new, innovative technique that allows scientists to create thermoelectric generators that are incredibly efficient.

A new 3D asymmetric double-Gaussian wake analytical model for horizontal-axis wind turbines

A new three-dimensional analytical model named 3DADG that is able to describe asymmetric evolution of wind turbine wake is proposed in this paper. Due to the combined effects of wind wheel rotation and wind shear effects wake attenuation shows asymmetric properties. However, existing wake analytical models fail to describe such unique properties. To solve this problem, spatial dependencies of the wake expansion rate and deficit coefficient are revealed to successfully present horizontal attenuations of the wake varying from asymmetric-double-Gaussian in the near and transition wake regions, and then to single-Gaussian in the far wake region. The wind shear effect is also considered in the model to include asymmetric vertical wake speed attenuation. This model is derived from the laws of mass and momentum conservation. It is verified through comparisons with the results of wind tunnel “blind test” and LES simulation. The model proposed is capable to show spatial evolution of wind turbine wake from a three-dimensional perspective. Sensitivities of thrust coefficient and turbulence intensity to the model are also investigated. It not only promotes development of wake analytical model but also provides a useful tool for power prediction and wake control of wind farms under wake effects.

Reversible Morphological Remodeling of Prefrontal and Hippocampal Serotonergic Fibers by Fluoxetine.

Serotonin-releasing fibers depart from the raphe nuclei to profusely innervate the entire central nervous system, displaying in some brain regions high structural plasticity in response to genetically induced abrogation of serotonin synthesis. Chronic fluoxetine treatment used as a tool to model peri-physiological, clinically relevant serotonin elevation is also able to cause structural rearrangements of the serotonergic fibers innervating the hippocampus. Whether this effect is limited to hippocampal-innervating fibers or extends to other populations of axons is not known. Here, we used confocal imaging and three-dimensional (3-D) modeling analysis to expand our morphological investigation of fluoxetine-mediated effects on serotonergic circuitry. We found that chronic treatment with a behaviorally active dose of fluoxetine affects the morphology and reduces the density of serotonergic axons innervating the medial prefrontal cortex, a brain region strongly implicated in the regulation of depressive- and anxiety-like behavior. Axons innervating the somatosensory cortex were unaffected, suggesting differential susceptibility to serotonin changes across cortical areas. Importantly, a 1-month washout period was sufficient to reverse morphological changes in both the medial prefrontal cortex and in the previously characterized hippocampus, as well as to normalize behavior, highlighting an intriguing relationship between axon density and an antidepressant-like effect. Overall, these results further demonstrate the bidirectional plasticity of defined serotonergic axons and provide additional insights into fluoxetine effects on the serotonergic system.

Analytical analysis of the thermal comfort of the occupants inside a truck cabin

Thermal comfort inside a truck cabin is a parameter that influences the well-being of the driver and passengers. From the very first steps of designing the driver’s seat of a vehicle, the driver’s well-being is taken into account through ergonomic parameters. To analyze the ultimate comfort inside a truck cabin, a simplified sketch of the cabin will be proposed. The three-dimensional analytical calculation model is solved using the Ansys program in the Fluid Flow (CFX) module. Through modeling and numerical simulations, the temperature inside a truck cabin, the mode of movement of the air flow and the speed of the air flow are determined. Following these tests, it is checked whether the thermal comfort conditions for the driver and passengers in a truck cabin are respected and fulfilled. These term comfort conditions are evaluated based on some comfort indices available in specialized literature.

Investigating a three-dimensional convolution recognition model for acoustic emission signal analysis during uniaxial compression failure of coal

Acoustic emission predicts coal sample failure, vital for early warnings and monitoring. The study emphasizes using acoustic emission to predict coal sample failure patterns and establish a discriminative model for monitoring. It employs a lightweight 3D convolutional model combining DenseNet with Group Convolution (GC) and the "squeeze-and-excitation" (SE) module. Coal samples from Xinglongzhuang Coal Mine underwent uniaxial compression, and a subset of experiments with prominent features was selected. The resulting acoustic emission parameters were then transformed into spatiotemporal image sequences for input to the model. Successfully identifying hazardous coal damage stages, all four network structures (DenseNet, DenseNet + GC, DenseNet + SE, DenseNet + GC + SE) achieved over 98.29% predictive accuracy in verification samples. The model exhibited a recall rate of over 98.02% for high-risk samples, effectively capturing spatiotemporal information. DenseNet + GC + SE showed a probability distribution focusing on different risk levels. By integrating group convolution and SE modules, this model significantly reduced both model and time complexity while preserving precision, enhancing efficiency. It effectively discerns diverse acoustic emission features through group convolution and evaluates their significance using the SE module. Compared to the traditional C3D neural network, this model greatly reduces complexity and time requirements while improving efficiency in distinguishing between various damage stages.

A novel intraocular pressure predicting method based on hyperelastic mechanical model of cornea

Measuring intraocular pressure (IOP) is crucial and remains challenging in diagnosing glaucoma, as it is associated with cornea deformation during inflation. In this study, a three-dimensional analytical model based on hyperelastic constitutive relationship to predict correlation between cornea vertex displacement and the IOP is proposed. The analytical model is validated by rigorous experiments. Rabbit corneas were selected for this study and their mechanical properties were obtained using uniaxial tensile tests. To mimic the environment in which the cornea exists, an artificial anterior chamber equipped with water-injection pipelines was constructed to study the relationship between the corneal vertex displacement with IOP value in practical situation. The experimental results of rabbits corneas prove that the IOP can be deduced based on the measured corneal vertex displacement by the analytical model. Furthermore, subtle difference occurs when comparing the calculated human IOPs with those measured by medical equipment, demonstrating that the proposed method is suitable for monitoring the IOP of human. This novel IOP predicting method provides new inspiration for the design of eyepieces, as well as the preoperative preparation for laser surgery and evaluation of corneal damage.

Three-dimensional modelling and morphometric analysis of skull of badger (Meles meles) with computed tomography images.

Morphometric measurements help to understand the skull morphology in different animal species, detect skull deformations and figure out their causes. The aim of this study is to make a three-dimensional (3D) modelling of the badger skull using computed tomography, to show its anatomical structures and to reveal the morphometric measurement values. Skull measurements were carried out using a digital calliper at 27 measurement points based on metric measurement points. After the scanned images were stored in Digital Imaging and Communications in Medicine format, they were transferred to MIMICS 20.1 (The Materialize Group) programme and 3D models the skulls were created. The surface area and volume values of the skulls were calculated on these models. The volume and surface area parameters were expressed as mean±SE. Four different indices were calculated using osteometric measurements. Statistical analyses were made by determining the mean value and standard deviation of the examined properties and the correlation coefficients among these properties. In the metric measurement points taken as a basis, the longest measurement in the skulls was the total length and its mean value was 124.60±0.64mm. The shortest measurement was the breadth dorsal to the external auditory meatus, and its mean value was 6.75±0.24mm. Consequently, statistical differences in the craniometric values of badgers' skulls were determined by using CT and 3D modelling software. In addition, it was concluded that the badger skull can be easily distinguished from other carnivore species by carrying out morphometric measurements.

Influence of Biotite Content on the Mechanical Response of Granite Using a Novel Three-Dimensional Grain-Based Model and Force Chain Analysis.

In this study, a three-dimensional grain-based model based on the discrete element method is utilized to replicate the heterogeneous structure of crystalline granite, and corresponding laboratory tests are conducted to validate the numerical conclusions. A novel model and an analytical method involving a multilevel force chain network are employed to quantitatively investigate the influence of mineral content on the mechanical behavior of granites. First, a set of granite specimens with varying biotite contents is constructed, and then, uniaxial compression tests are conducted. The effects of the mineral content on the mechanical behavior, force chain network characteristics, and fracture resistance of granite specimens are quantitatively analyzed. The results indicate an inverse relationship between the biotite (VB) content and the load-bearing capacity of granite under uniaxial compression conditions. As VB increases, the number of contacts within the biotite structure increases, as does the force chain distribution density within the biotite structure, while the force chain distribution density in other intragranular structures correspondingly decreases. The average values and sum values of all of the force chains in the whole specimen decrease with increasing VB. Among the various structures, intragranular structures exhibit the highest fracture resistance, whereas intergranular structures exhibit lower resistance.