scholarly journals Thermal Analysis of Directional Freezing Based Graphene Aerogel Three-Dimensional Printing Process

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Guanglei Zhao ◽  
Dong Lin ◽  
Chi Zhou
Keyword(s):  
Three Dimensional ◽  
Process Efficiency ◽  
Transfer Model ◽  
Graphene Aerogel ◽  
Flexible Tool ◽  
Efficiency And Effectiveness ◽  
Simulation And Experiment ◽  
Printed Materials ◽  
Directional Freezing ◽  
And Control

A novel directional freezing based three-dimensional (3D) printing technique is applied to fabricate graphene aerogel (GA). Thermal property of the graphene ink is one of the key impacts on the material morphology and process efficiency/reliability. We develop a heat transfer model to predict temperature evolution of the printed materials and then estimate layer waiting time based on it. The proposed technique can not only improve the process efficiency and reliability but also serve as a flexible tool to predict and control the microstructure of the printed graphene aerogels. Both the simulation and experiment results demonstrate the efficiency and effectiveness of the proposed approach.

Thermal Analysis on Directional Freezing of Nano Aqueous Suspensions in Graphene Aerogel 3D Printing Process

2016 ◽  
Author(s):  
Guanglei Zhao ◽  
Chi Zhou ◽  
Dong Lin
Keyword(s):  
3D Printing ◽  
Waiting Time ◽  
Temperature Evolution ◽  
Process Efficiency ◽  
Transfer Model ◽  
Graphene Aerogel ◽  
Flexible Tool ◽  
Printed Materials ◽  
Directional Freezing ◽  
Efficiency And Reliability

This paper presented a novel 3D printing technique to fabricate graphene aerogel based on directional freezing. Thermal property of the graphene ink is one of key factors in this process which affects the material integrity and morphology as well as process efficiency and reliability. The major objective of this paper is to develop a heat transfer model to efficiently and reliably predict the temperature evolution of the printed materials and the waiting time between the layers for any input geometry. The simulation results show that the input geometry significantly affects the temperature evolution and waiting time. The proposed technique can not only improve the process efficiency and reliability, it can also serve as a flexible tool to predict and control the microstructure of the printed graphene aerogels.

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

scholarly journals A three-dimensional polyoxometalate/graphene aerogel as a highly efficient and recyclable absorbent for oil/water separation

2021 ◽  
Vol 36 (1) ◽  
pp. 189-197
Author(s):  
Sen Wang ◽  
Xiao Wang ◽  
Xiao-yu Shi ◽  
Cai-xia Meng ◽  
Cheng-lin Sun ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Graphene Aerogel ◽  
Water Separation ◽  
Highly Efficient ◽  
Oil Water Separation ◽  
Oil Water

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

Cyclopean Vision, Size Estimation, and Presence in Orthostereoscopic Images

2001 ◽  
Vol 10 (3) ◽  
pp. 312-330 ◽  
Author(s):  
Bernard Harper ◽  
Richard Latto
Keyword(s):  
Visual System ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychophysical Experiment ◽  
Size Estimation ◽  
Human Form ◽  
Image Capture ◽  
Series Of Experiments ◽  
Abstract Shapes ◽  
And Control

Stereo scene capture and generation is an important facet of presence research in that stereoscopic images have been linked to naturalness as a component of reported presence. Three-dimensional images can be captured and presented in many ways, but it is rare that the most simple and “natural” method is used: full orthostereoscopic image capture and projection. This technique mimics as closely as possible the geometry of the human visual system and uses convergent axis stereography with the cameras separated by the human interocular distance. It simulates human viewing angles, magnification, and convergences so that the point of zero disparity in the captured scene is reproduced without disparity in the display. In a series of experiments, we have used this technique to investigate body image distortion in photographic images. Three psychophysical experiments compared size, weight, or shape estimations (perceived waist-hip ratio) in 2-D and 3-D images for the human form and real or virtual abstract shapes. In all cases, there was a relative slimming effect of binocular disparity. A well-known photographic distortion is the perspective flattening effect of telephoto lenses. A fourth psychophysical experiment using photographic portraits taken at different distances found a fattening effect with telephoto lenses and a slimming effect with wide-angle lenses. We conclude that, where possible, photographic inputs to the visual system should allow it to generate the cyclopean point of view by which we normally see the world. This is best achieved by viewing images made with full orthostereoscopic capture and display geometry. The technique can result in more-accurate estimations of object shape or size and control of ocular suppression. These are assets that have particular utility in the generation of realistic virtual environments.

Use of shape-from-shading to estimate three-dimensional architecture in the small intestinal lumen of celiac and control patients

2013 ◽  
Vol 111 (3) ◽  
pp. 676-684 ◽  
Author(s):  
Edward J. Ciaccio ◽  
Christina A. Tennyson ◽  
Govind Bhagat ◽  
Suzanne K. Lewis ◽  
Peter H.R. Green
Keyword(s):  
Three Dimensional ◽  
Shape From Shading ◽  
Intestinal Lumen ◽  
Small Intestinal ◽  
And Control
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