scholarly journals Three-Dimensional Model of the Moon with Semantic Information of Craters Based on Chang’e Data

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 959
Author(s):  
Yunfan Lu ◽  
Yifan Hu ◽  
Jun Xiao ◽  
Lupeng Liu ◽  
Long Zhang ◽  
...  
Keyword(s):  
Reference Frame ◽  
3D Model ◽  
Semantic Information ◽  
Three Dimensional ◽  
Impact Craters ◽  
Detection Methods ◽  
The Moon ◽  
Three Dimensional Model ◽  
Data Set ◽  
The Impact

China’s Chang’e lunar exploration project obtains digital orthophoto image (DOM) and digital elevation model (DEM) data covering the whole Moon, which are critical to lunar research. The DOM data have three resolutions (i.e., 7, 20 and 50 m), while the DEM has two resolutions (i.e., 20 and 50 m). Analysis and research on these image data effectively help humans to understand the Moon. In addition, impact craters are considered the most basic feature of the Moon’s surface. Statistics regarding the size and distribution of impact craters are essential for lunar geology. In existing works, however, the lunar surface has been reconstructed less accurately, and there is insufficient semantic information regarding the craters. In order to build a three-dimensional (3D) model of the Moon with crater information using Chang‘e data in the Chang‘e reference frame, we propose a four-step framework. First, software is implemented to annotate the lunar impact craters from Chang’e data by complying with our existing study on an auxiliary annotation method and open-source software LabelMe. Second, auxiliary annotation software is adopted to annotate six segments in the Chang’e data for an overall 25,250 impact crater targets. The existing but inaccurate craters are combined with our labeled data to generate a larger dataset of craters. This data set is analyzed and compared with the common detection data. Third, deep learning detection methods are employed to detect impact craters. To address the problem attributed to the resolution of Chang’e data being too high, a quadtree decomposition is conducted. Lastly, a geographic information system is used to map the DEM data to 3D space and annotate the semantic information of the impact craters. In brief, a 3D model of the Moon with crater information is implemented based on Chang’e data in the Chang‘e reference frame, which is of high significance.

scholarly journals Modeling and Validation of Heliostat Deformation due to Static Loading

2011 ◽  
Author(s):  
Adam C. Moya ◽  
Clifford K. Ho
Keyword(s):  
Finite Element ◽  
Structural Stability ◽  
Three Dimensional ◽  
Test Facility ◽  
Optical Performance ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Data Set ◽  
Static Test ◽  
The Impact

Accurate and reliable models are necessary to predict the performance and efficiencies of concentrating solar power plant components and systems such as heliostats and central receiver systems. Heliostat performance is impacted from effects such as wind and gravity, and understanding the impact of these loads on the optical performance can yield heliostat designs that are potentially cheaper, while maintaining required structural stability. Finite element models of heliostats at the National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories in Albuquerque, NM, were developed to simulate displacements under different loading scenarios. Solidworks was used to develop the three-dimensional model of the NSTTF heliostat, and Solidworks Simulation was used to perform the finite element analysis with simulated loads along different points of the heliostat. Static displacement tests were performed on the NSTTF heliostat in order to validate these FEA models. The static test results provide us with a data set in which to properly calibrate the FEA model to better represent the NSTTF heliostat for future simulations of optical performance with impacts of wind and gravity sag. In addition to a single model validation, this real world test provides a method to validate and understand the structural stability of a heliostat under static loads.

scholarly journals Self-Secondaries Formed by Cold Spot Craters on the Moon

2021 ◽  
Vol 13 (6) ◽  
pp. 1087
Author(s):  
Yiren Chang ◽  
Zhiyong Xiao ◽  
Yang Liu ◽  
Jun Cui
Keyword(s):  
Systematic Investigation ◽  
Impact Craters ◽  
Spatial Density ◽  
Cold Spot ◽  
The Moon ◽  
Potential Threat ◽  
Frequency Distributions ◽  
Crater Size ◽  
The Impact ◽  
Density Pattern

Self-secondaries are a population of background secondaries, and they have been observed on top of impact melt and ballistically emplaced ejecta deposits on various planetary bodies. Self-secondaries are formed by impacts of sub-vertically launched ejecta, but the launch mechanism is not confirmed. The potential threat of self-secondaries to the theoretical and applicable reliability of crater chronology has been noted, but not constrained. Hitherto discovered self-secondaries were located around complex impact craters, but their potential existence around simple craters has not been discovered. Here we report the first discovery of self-secondaries around lunar cold spot craters, which are an extremely young population of simple craters formed within the past ~1 million years on the Moon. Self-secondaries are widespread on layers of cascading flow-like ejecta deposits around cold spot craters. The spatial density of self-secondaries dwarfs that of potential primary craters. The spatial distribution of self-secondaries is highly heterogeneous across the ejecta deposits. With respect to the impactor trajectory that formed cold spot craters, self-secondaries formed at the downrange of the ejecta deposits have the largest spatial density, while those at the uprange have the smallest density. This density pattern holds for all cold spot craters that were formed by non-vertical impacts, but self-secondaries do not exhibit other systematic density variations at different radial distances or at other azimuths with respect to the impactor trajectory. Among known mechanics of ejecting materials to the exterior of impact craters, impact spallation is the most likely scenario to account for the required large ejection velocities and angles to form self-secondaries. The production population of self-secondaries is estimated based on the highly diverse crater size-frequency distributions across the ejecta deposits of cold spot craters. For a better understanding of the impact history on the Moon, a systematic investigation for the effect of self-secondaries on lunar crater chronology is required.

Stress-strain curve of paper revisited

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland
Keyword(s):  
Three Dimensional ◽  
Strain Curve ◽  
Failure Behavior ◽  
Three Dimensional Model ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fiber Network ◽  
Bonding Parameters ◽  
Particle Level ◽  
The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

scholarly journals Architecture Studio Learning: Strategy to Achieve Architects Competence

2018 ◽  
Vol 41 ◽  
pp. 04004 ◽  
Author(s):  
Ahmad Saifudin Mutaqi
Keyword(s):  
Learning Process ◽  
Learning Strategy ◽  
Three Dimensional ◽  
Learning Model ◽  
Final Report ◽  
Three Dimensional Model ◽  
Education Standards ◽  
Research Technology ◽  
Study Materials ◽  
The Impact

In most Schools of Architecture, Architecture Studio is at the core of the architectural learning process. In the process, students are trained to have the skills of architectonic spaces design based on the study of the site, its function, and its aesthetics. Students are also trained to have awareness and understanding about the impact of their design on the surrounding environment, both physically and socially. Also, students are trained to present their designs in various forms such as visual graphics, verbal narratives, and three dimensional model animations. Indonesian Association of School of Architecture (APTARI Asosiasi Perguruan Tinggi Arsitektur Indonesia) and Indonesian Institute of Architects (IAI - Ikatan Arsitek Indonesia) has formulated an education Standards, Curriculum, and Achievements of Architect Professional Program to be referred by Ministry of Research, Technology, and Higher Education (KEMENRISTEKDIKTI – Kementerian Riset, Teknologi, danPerguruanTinggi) as the guidance for the implementation of Architect Professional Program (PPA - Pendidikan Profesi Arsitek) in Indonesia. One of the eight recommendations is the PPA Content Standard which contains the learning for the achievement of IAI Architect Competencies through the recommended study materials. However, the recommended study materials did not indicate the activity of the Architecture Studio learning model (Final Report of APTARI Part II and IAI). Will architect’s competence be achieved if the learning process withoutarchitectural studio learning model? The formulation of the curriculum that is developed independently by the IAI recommends the learning of Architectural Studio as Professional Studio. The size of the SKS is large enough to enable someone who follows the lesson to intensively gain experience in designing the building as a real architectural work. This Architecture Studio learning model is interpreted by PPAr organizer universities with various forms, among others: (1) apprenticeship of architects; (2) supervised studios; And (3) project simulation studio. From various models of Architecture learning model mentioned above, all aim to achieve 13 Architect Competence as formulated by IAI. Which model is effective in learning the Architectural Studio mentioned above? This exploratory study would like to compare the three forms of Architecture Studio learning model to see how much the achievement of the targeted competencies by measuring the success of Competency Test activities still use the standards implemented by LPJK by involving assessors from IAI. The results of the comparison will show the compatibility of the implementation of the Architecture Studio learningmodel what is considered effective. These findings will certainly benefit the development of future PPAr implementation, especially if the Architecture Studio model can be commensurate with the studios developed by the School of Architecture in various countries, at least in the region of 21 member countries ARCASIA.

Transitional impact craters on the Moon: Insight into the effect of target lithology on the impact cratering process

2018 ◽  
Author(s):  
Gordon R. Osinski ◽  
Elizabeth A. Silber ◽  
Jacqueline Clayton ◽  
Richard A. F. Grieve ◽  
Kayle Hansen ◽  
...  
Keyword(s):  
Impact Craters ◽  
The Moon ◽  
Impact Cratering ◽  
The Impact ◽  
Insight Into

scholarly journals Impact of Urban Undersea Tunnel Longitudinal Slope on the Visual Characteristics of Drivers

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Shoushuo Wang ◽  
Zhigang Du ◽  
Fangtong Jiao ◽  
Libo Yang ◽  
Yudan Ni
Keyword(s):  
Repeated Measures ◽  
Three Dimensional ◽  
Fixation Time ◽  
Eye Tracker ◽  
Three Dimensional Model ◽  
Longitudinal Slope ◽  
Visual Characteristics ◽  
The Difference ◽  
Vehicle Test ◽  
The Impact

This study aims to investigate the impact of the urban undersea tunnel longitudinal slope on the visual characteristics of drivers. 20 drivers were enrolled to conduct the real vehicle test of the urban undersea tunnel. First, the data of average fixation time and visual lobe were collected by an eye tracker. The differential significance was tested using the one-way repeated measures analysis of variance (ANOVA). Then, the difference between the up-and-down slope (direction) factor and the longitudinal slope (percent) factor on the two indexes were analyzed using the two-way repeated measures ANOVA. Second, by constructing a Lorentz model, the impact of the longitudinal slope on the average fixation time and the visual lobe were analyzed. Besides, a three-dimensional model of the longitudinal slope, average fixation time, and visual lobe was quantified. The results showed that the average fixation time and visual lobe under different longitudinal slopes markedly differed when driving on the uphill and downhill sections. The average fixation time and visual lobe under two factors were markedly different. Moreover, with an increase in the longitudinal slope, the average fixation time exhibited a trend of increasing first then decreasing; the visual lobe exhibited a trend of decreasing first and then increasing. The average fixation time reached the minimum and maximum value when the slope was 2.15% and 4.0%, whereas the visual lobe reached the maximum and minimum value when the slope was 2.88% and 4.0%. Overall, the longitudinal slope exerted a great impact on the visual load of the driver.

Finite-element analysis of multi-body contacts for pile driving using a hydraulic pile hammer

2011 ◽  
Vol 225 (5) ◽  
pp. 1153-1161 ◽  
Author(s):  
Y Guo ◽  
J P Hu ◽  
L Y Zhang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Test Point ◽  
Pile Driving ◽  
Penalty Function Method ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Material Choice ◽  
Multi Body ◽  
The Impact

This article treats the pile driving as multi-body dynamic contacts. By using the penalty function method and three-dimensional model of finite-element method, the dynamic process of pile driving is acquired and a method for choosing the cushion material of the hydraulic pile hammer to improve driving efficiency is proposed. The process of pile driving in the real situation of an industrial experiment is simulated. The results of stress on test point are consistent with the test point. By analysing the stress distributed along the direction of pile radius and pile axis, the rule of the stress distribution on the pile is concluded. The rule for cushion material choice is obtained by comparing the influence for the impact stress with different elastic modulus ratio of the hammer cushion to the pile and the pile cushion to the pile.

Regimes of Dry Convection above Wildfires: Sensitivity to Fire Line Details

2010 ◽  
Vol 67 (3) ◽  
pp. 611-632 ◽  
Author(s):  
Michael T. Kiefer ◽  
Matthew D. Parker ◽  
Joseph J. Charney
Keyword(s):  
Line Shape ◽  
3D Model ◽  
Three Dimensional ◽  
Vertical Wind Shear ◽  
Heating Rates ◽  
3D Simulations ◽  
Complex Phenomena ◽  
2D And 3D ◽  
The Impact ◽  
Dry Convection

Abstract Fire lines are complex phenomena with a broad range of scales of cross-line dimension, undulations, and along-line variation in heating rates. While some earlier studies have examined parcel processes in two-dimensional simulations, the complexity of fire lines in nature motivates a study in which the impact of three-dimensional fire line details on parcel processes is examined systematically. This numerical modeling study aims to understand how fundamental processes identified in 2D simulations operate in 3D simulations where the fire line is neither straight nor uniform in intensity. The first step is to perform simulations in a 3D model, with no fire line undulations or inhomogeneity. In general, convective modes simulated in the 2D model are reproduced in the 3D model. In one particular case with strong vertical wind shear, new convection develops separate from the main line of convection as a result of local changes to parcel speed and heating. However, in general the processes in the 2D and 3D simulations are identical. The second step is to examine 3D experiments wherein fire line shape and along-line inhomogeneity are varied. Parcel heating, as well as convective mode, is shown to exhibit sensitivity to fire line shape and along-line inhomogeneity.

scholarly journals Forecasting of Surface Currents via Correcting Wind Stress with Assimilation of High-Frequency Radar Data in a Three-Dimensional Model

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Ren ◽  
Stephen Nash ◽  
Michael Hartnett
Keyword(s):  
Data Assimilation ◽  
High Frequency ◽  
Three Dimensional ◽  
Hf Radar ◽  
Surface Velocity ◽  
Shear Stresses ◽  
Surface Currents ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The Impact

This paper details work in assessing the capability of a hydrodynamic model to forecast surface currents and in applying data assimilation techniques to improve model forecasts. A three-dimensional model Environment Fluid Dynamics Code (EFDC) was forced with tidal boundary data and onshore wind data, and so forth. Surface current data from a high-frequency (HF) radar system in Galway Bay were used for model intercomparisons and as a source for data assimilation. The impact of bottom roughness was also investigated. Having developed a “good” water circulation model the authors sought to improve its forecasting ability through correcting wind shear stress boundary conditions. The differences in surface velocity components between HF radar measurements and model output were calculated and used to correct surface shear stresses. Moreover, data assimilation cycle lengths were examined to extend the improvements of surface current’s patterns during forecasting period, especially for north-south velocity component. The influence of data assimilation in model forecasting was assessed using a Data Assimilation Skill Score (DASS). Positive magnitude of DASS indicated that both velocity components were considerably improved during forecasting period. Additionally, the improvements of RMSE for vector direction over domain were significant compared with the “free run.”

scholarly journals Simulation Technique of Kinematic Processes in the Vehicle Steering Linkage

2018 ◽  
Vol 7 (4.3) ◽  
pp. 120 ◽  
Author(s):  
Sergii Chernenko ◽  
Eduard Klimov ◽  
Andrii Chernish ◽  
Olexandr Pavlenko ◽  
Volodymyr Kukhar
Keyword(s):  
Three Dimensional ◽  
Simulation Technique ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Design Data ◽  
Power Characteristics ◽  
Left And Right ◽  
Turning Radius ◽  
The Impact ◽  
The Mathematical Model

The results of the investigation of the turning kinematics of the steerable wheels of the KrAZ-7634NE off-road vehicle with a wheel formula 8x8 and two front steer axles are given. The theoretical relations between the steer angles of the steerable wheels on the basis of the scheme of double-axle steering turning of the vehicle are shown. The mathematical model of flat four-bar vehicle steering linkage is developed, it determines the relation between the steering linkage left and right steering arms turning angles at any turning radius of the vehicle. KrAZ-7634HE steering three-dimensional model was created and simulation technique of its work was carried out using Creo software. It has been shown that the flat steering linkage model provides sufficient accuracy of calculations in analysis of turning kinematics. The design data can be used for any vehicles that have a similar steering linkage, they allow to analyze the impact of the vehicle design parameters on the turning kinematics and optimize them. Further study of the impact of the kingpin inclinations on the steering linkage kinematic and power characteristics are required.  

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