A 3D Reconstruction Framework of Buildings Using Single Off-Nadir Satellite Image

A novel framework for 3D reconstruction of buildings based on a single off-nadir satellite image is proposed in this paper. Compared with the traditional methods of reconstruction using multiple images in remote sensing, recovering 3D information that utilizes the single image can reduce the demands of reconstruction tasks from the perspective of input data. It solves the problem that multiple images suitable for traditional reconstruction methods cannot be acquired in some regions, where remote sensing resources are scarce. However, it is difficult to reconstruct a 3D model containing a complete shape and accurate scale from a single image. The geometric constraints are not sufficient as the view-angle, size of buildings, and spatial resolution of images are different among remote sensing images. To solve this problem, the reconstruction framework proposed consists of two convolutional neural networks: Scale-Occupancy-Network (Scale-ONet) and model scale optimization network (Optim-Net). Through reconstruction using the single off-nadir satellite image, Scale-Onet can generate water-tight mesh models with the exact shape and rough scale of buildings. Meanwhile, the Optim-Net can reduce the error of scale for these mesh models. Finally, the complete reconstructed scene is recovered by Model-Image matching. Profiting from well-designed networks, our framework has good robustness for different input images, with different view-angle, size of buildings, and spatial resolution. Experimental results show that an ideal reconstruction accuracy can be obtained both on the model shape and scale of buildings.

Comment on “Size dependence of bubble wetting on surfaces: breakdown of contact angle match between small sized bubbles and droplets” by H. Zhang and X. Zhang, Nanoscale, 2019, 11, 2823

The theoretical arguments of the paper commented contain errors and cannot explain the simulation results. We suggest that line tension and adsorptions at interfaces may be responsible for a difference in the contact angle size dependencies for droplets and bubbles.

The Use of a Novel Term Helps Preschoolers Learn the Concept of Angle: An Intervention Study With Chinese Preschool Children

Angle is an important concept in geometry. Young children have difficulty separating angle size from other dimensions such as the length of angle sides, perhaps due to whole-object bias in word learning. The present study used the pre-test–training–post-test design to investigate the effectiveness of two ways of separating angle from angle size in 3–6-year-old Chinese preschoolers. A total of 228 children were given a pre-test and 219 of them failed the crucial test. 168 of the 219 children were present at school during the training phase and were randomly assigned to three groups: the “toma” group (n = 57), which received training to call the whole angle figure as “toma” and angle size as angle size; the “angle/angle size” group (n = 56), which received the training of separating “angle” from “angle size”; and the control group (n = 55), which used “angle size” alone to represent both the overall angle figure and angle size. Results showed that the “toma” group improved significantly more than the other two groups, the latter of which did not differ from each other. These results suggest that it is insufficient to have two separate words/phrases (angle and angle size) for children to learn to differentiate angle from angle size, perhaps due to their shared usage of the word angle. Instead, the use of a novel term is necessary and sufficient to improve learning. Implications for preschool education are discussed.

Effect of Nozzle Angle, Size and Pressure on Spray Distribution based on Laboratory Conditions

The objective of this study is to investigate spray parameters for different 40°– 95° even flat fan nozzle angles for banding spraying application, such as spray pattern width and spray volumetric distribution at pressures of 2 and 3bar using different nozzle sizes (0.15, 0.2, 0.3, 0.4 gpm). Spray distribution data was extracted from spray analyzer system or patternator. The results showed that nozzle angle and pressure significantly affected the spray pattern width. In addition, as the nozzle size increased, the liquid volume and the peak height under the nozzle center increased. These results suggest that the use of bigger nozzle angles improved the spray volumetric distribution.

Measurement of thumb pronation and palmar abduction angles with a small motion sensor: a comparison with Kapandji scores

The Kapandji score is used widely to record thumb opposition and is the only alternative to angular measurements. We aimed to verify the extent to which the Kapandji score reflects the angle of pronation. We recruited volunteers with unaffected upper limbs (33 hands) and patients with carpal tunnel syndrome (20 hands). We attached a small gyroscope to the thumb metacarpal and measured the pronation and palmar abduction angles at each position of the Kapandji score in both groups. The Kapandji score showed a strong ceiling effect, and the increase in angle size at each Kapandji score levelled off around a score of 6 in both groups. A Kapandji score greater than 6 does not necessarily reflect thumb opposition. Level of Evidence: III

Simulation Study of Nozzle in Fire Engine Based on Fluent

Focus on the technology and requirements of nozzle in fire engine to optimize the ability of blasting of nozzle, this paper built the model of fluid in nozzle, and simulation studied based on Fluent. This paper analysis the stage of nozzle, contraction angle, size of entrance and slenderness ratio as the influencing factors, supplied the reliable theoretical foundation for the design and structural improvement of nozzle in fire engine.