scholarly journals Use of terrestrial laser scanning for engineering geological applications on volcanic rock slopes – an example from Madeira island (Portugal)

2011 ◽  
Vol 11 (3) ◽  
pp. 807-817 ◽  
Author(s):  
H. T. Nguyen ◽  
T. M. Fernandez-Steeger ◽  
T. Wiatr ◽  
D. Rodrigues ◽  
R. Azzam
Keyword(s):  
Volcanic Rock ◽  
Laser Scanning ◽  
Additional Data ◽  
Laser Scanner ◽  
Block Size ◽  
Rock Slopes ◽  
Madeira Island ◽  
Detailed Structural Analysis ◽  
Average Block

Abstract. This study focuses on the adoption of a modern, widely-used Terrestrial Laser Scanner (TLS) application to investigate volcanic rock slopes in Ribeira de João Gomes valley (Funchal, Madeira island). The TLS data acquisition in May and December 2008 provided information for a characterization of the volcanic environment, detailed structural analysis and detection of potentially unstable rock masses on a slope. Using this information, it was possible to determine specific parameters for numerical rockfall simulations such as average block size, shape or potential sources. By including additional data, such as surface roughness, the results from numerical rockfall simulations allowed us to classify different hazardous areas based on run-out distances, frequency of impacts and related kinetic energy. Afterwards, a monitoring of hazardous areas can be performed in order to establish a rockfall inventory.

scholarly journals CHANGE ANALYSIS OF LASER SCANS OF LABORATORY ROCK SLOPES SUBJECT TO WAVE ATTACK TESTING

2017 ◽  
Vol IV-2/W4 ◽  
pp. 139-147
Author(s):  
Y. Shen ◽  
R. Lindenbergh ◽  
B. Hofland ◽  
R. Kramer
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Point Clouds ◽  
High Energy ◽  
Point Of View ◽  
Rock Surface ◽  
Rock Slopes ◽  
Surface Slope ◽  
Change Analysis ◽  
Before And After

For better understanding how coastal structures with gentle slopes behave during high energy events, a wave attack experiment representing a storm of 3000 waves was performed in a flume facility. Two setups with different steepness of slope were compared under the same conditions. In order to quantify changes in the rock slopes after the wave attack, a terrestrial laser scanner was used to obtain 3D coordinates of the rock surface before and after each experiment. Next, through a series of processing steps, the point clouds were converted to a suitable 2D raster for change analysis. This allowed to estimate detailed and quantitative change information. The results indicate that the area around the artificial coast line, defined as the intersection between sloped surface and wave surface, is most strongly affected by wave attacks. As the distances from the sloped surface to the waves are shorter, changes for the mildly sloped surface, slope 1 (1 : 10), are distributed over a larger area compared to the changes for the more steeply sloped surface, slope 2 (1 : 5). The results of this experiment show that terrestrial laser scanning is an effective and feasible method for change analysis of rock slopes in a laboratory setting. Most striking results from a process point of view is that the transport direction of the rocks change between the two different slopes: from seaward transport for the steeper slope to landward transport for the milder slope.

Results of studying the dimensional accuracy of the bases of complete removable prostheses made using 3D printing and traditional technologies

2020 ◽  
pp. 34-39
Author(s):  
Vokulova Yu.A. Vokulova ◽  
E.N. Zhulev
Keyword(s):  
3D Printing ◽  
Traditional Method ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Digital Technologies ◽  
Dimensional Accuracy ◽  
3D Printer ◽  
Significance Level ◽  
Average Value ◽  
The Difference

This article presents the results of studying the dimensional accuracy of the bases of complete removable prostheses made using a 3D printer and the traditional method. Bases of complete removable prostheses were made using an intraoral laser scanner iTero Cadent (USA) and a 3D printer Asiga Max UV (Australia). To study the dimensional accuracy of the bases of complete removable prostheses, we used the DentalCAD 2.2 Valletta software. The Nonparametric Wilcoxon W-test was used for statistical analysis of the obtained data. We found that the average value of the difference with the standard for bases made using digital technologies is 0.08744±0.0484 mm. The average value of the difference with the standard for bases made by the traditional method is 0.5654±0.1611 mm. Based on these data, we concluded that the bases of complete removable prostheses made using modern digital technologies (intraoral laser scanning and 3D printer) have a higher dimensional accuracy compared to the bases of complete removable prostheses made using the traditional method with a significance level of p<0.05 (Wilcoxon's W-test=0, p=0.031). Keywords: digital technologies in dentistry, digital impressions, intraoral scanner, 3D printing, ExoCAD, complete removable dentures.

STABILITY ANALYSIS OF WEATHERED VOLCANIC ROCK SLOPES IN THE CARIBBEAN

2019 ◽  
Author(s):  
Rachel Capps ◽  
◽  
Scott Brame ◽  
Audrey Crafton
Keyword(s):  
Stability Analysis ◽  
Volcanic Rock ◽  
Rock Slopes ◽  
The Caribbean

scholarly journals Estimation of Vegetation-Induced Flow Resistance for Hydraulic Computations Using Airborne Laser Scanning Data

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1864
Author(s):  
Peter Mewis
Keyword(s):  
Laser Scanning ◽  
Flow Resistance ◽  
Laser Scanner ◽  
Airborne Laser Scanning ◽  
Density Parameter ◽  
Vegetation Density ◽  
Airborne Laser Scanner ◽  
Airborne Laser ◽  
Bed Roughness ◽  
Available Information

The effect of vegetation in hydraulic computations can be significant. This effect is important for flood computations. Today, the necessary terrain information for flood computations is obtained by airborne laser scanning techniques. The quality and density of the airborne laser scanning information allows for more extensive use of these data in flow computations. In this paper, known methods are improved and combined into a new simple and objective procedure to estimate the hydraulic resistance of vegetation on the flow in the field. State-of-the-art airborne laser scanner information is explored to estimate the vegetation density. The laser scanning information provides the base for the calculation of the vegetation density parameter ωp using the Beer–Lambert law. In a second step, the vegetation density is employed in a flow model to appropriately account for vegetation resistance. The use of this vegetation parameter is superior to the common method of accounting for the vegetation resistance in the bed resistance parameter for bed roughness. The proposed procedure utilizes newly available information and is demonstrated in an example. The obtained values fit very well with the values obtained in the literature. Moreover, the obtained information is very detailed. In the results, the effect of vegetation is estimated objectively without the assignment of typical values. Moreover, a more structured flow field is computed with the flood around denser vegetation, such as groups of bushes. A further thorough study based on observed flow resistance is needed.

The Steam Turbine Retrofitting of Six Boiling Water Reactor Units Using Innovative Engineering and Laser Scanning Techniques

2009 ◽  
Author(s):  
Mike Jones ◽  
David J. Nelmes
Keyword(s):  
Steam Turbine ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Boiling Water ◽  
Boiling Water Reactors ◽  
Extensive Experience ◽  
Turbine Generators ◽  
The Usa ◽  
Water Reactors ◽  
Scan Data

Alstom Power is executing the steam turbine retrofit of six nuclear units for Exelon Generation in the USA. The existing turbine-generators are an 1800 RPM General Electric design originally rated at 912 MWe and 1098 MWe and powered by Boiling Water Reactors. 18 Low Pressure inner modules will be replaced, with the first due to be installed in March 2010. This project is particularly challenging — the aggressive retrofit installation schedule is compounded by the requirement to handle radioactively contaminated equipment and also comply with demanding regulations applicable to BWR plant. The author’s company has extensive experience in the steam turbine retrofit business, having supplied around 800 retrofit cylinders globally since the 1970’s. However, this LP upgrade challenges the established techniques used in the business and requires extraordinary effort. Traditional retrofit engineering and installation principles have been interrogated and developed to meet the specific requirements of this project. Innovative techniques are introduced, including the extensive use of the Leica HDS 6000 laser scanner to model the existing plant. The approach has advanced the field of steam turbine retrofit design and installation significantly. The first section of this paper focuses on the extraordinary considerations of the project and the challenges surrounding BWR plant. The second part describes the laser scanning technique and the application of scan data. It outlines the innovative solutions which have been developed.

scholarly journals Laser scanning cytometry in the characterization of the proapoptotic effects of transiently transfected genes in cerebellar granule neurons

2006 ◽  
Vol 69A (11) ◽  
pp. 1114-1122 ◽  
Author(s):  
Brendan Bingham ◽  
Smita Kotnis ◽  
Barbara McHendry-Rinde ◽  
Ru Shen ◽  
Andrew Wood ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Cerebellar Granule Neurons ◽  
Granule Neurons ◽  
Cerebellar Granule ◽  
Laser Scanning Cytometry

Extraction of road boundary from MLS data using laser scanner ground trajectory

2021 ◽  
Vol 13 (1) ◽  
pp. 690-704
Author(s):  
Lichun Sui ◽  
Jianfeng Zhu ◽  
Mianqing Zhong ◽  
Xue Wang ◽  
Junmei Kang
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Boundary Tracking ◽  
The Road ◽  
Navigation Data ◽  
Vehicle Trajectories ◽  
Upward Slope ◽  
Tracking Model ◽  
On The Road ◽  
Boundary Model

Abstract Various means of extracting road boundary from mobile laser scanning data based on vehicle trajectories have been investigated. Independent of positioning and navigation data, this study estimated the scanner ground track from the spatial distribution of the point cloud as an indicator of road location. We defined a typical edge block consisting of multiple continuous upward fluctuating points by abrupt changes in elevation, upward slope, and road horizontal slope. Subsequently, such edge blocks were searched for on both sides of the estimated track. A pseudo-mileage spacing map was constructed to reflect the variation in spacing between the track and edge blocks over distance, within which road boundary points were detected using a simple linear tracking model. Experimental results demonstrate that the ground trajectory of the extracted scanner forms a smooth and continuous string just on the road; this can serve as the basis for defining edge block and road boundary tracking algorithms. The defined edge block has been experimentally verified as highly accurate and strongly noise resistant, while the boundary tracking algorithm is simple, fast, and independent of the road boundary model used. The correct detection rate of the road boundary in two experimental data is more than 99.2%.

scholarly journals Detecting the Competition between Moso Bamboos and Broad-Leaved Trees in Mixed Forests Using a Terrestrial Laser Scanner

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 520 ◽  
Author(s):  
Yingjie Yan ◽  
Mingpeng Xia ◽  
Shaohui Fan ◽  
Meichun Zhan ◽  
Fengying Guan
Keyword(s):  
Spatial Structure ◽  
Laser Scanning ◽  
Mixed Forest ◽  
Laser Scanner ◽  
Phyllostachys Pubescens ◽  
Mixed Forests ◽  
Individual Trees ◽  
Convex Hull Algorithm ◽  
Intensity Of Competition ◽  
Multiple Interactions

The growth of individual trees in a forest is affected by many factors, a crucial one being the intensity of competition among trees, because it affects the spatial structure of the forest and is in turn influenced by silvicultural practices. In a mixed forest in particular, the growth of trees is affected by multiple interactions. To analyse the competition between moso bamboo (Phyllostachys pubescens (Pradelle) Mazel ex J.Houz.) and broad-leaved trees in a mixed forest, data were extracted by sampling six spots within such a forest using terrestrial laser scanning (TLS). The convex hull algorithm was used for calculating the overlap volume between the crowns of the broad-leaved trees and the bamboo canopy. Bamboos growing at least 3 m away from any of the broad-leaved trees were the most numerous and the diameter at breast height (DBH) is larger than those growing closer than that, which suggests that broad-leaved trees suppressed the growth of bamboo if they are closer but promote it beyond 3 m up to a point at which the distance is too great for any such effect. The modified Hegyi’s competition index was constructed based on the canopy factor, which may better describe the competitive interaction among the trees and bamboos. Using TLS can enhance our understanding of the competition among trees in mixed forests and help in planning the spatial structure of such forests in general and provide a benchmark for choosing planting distances in particular.

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