Testing and Performance Evaluation of Fixed Terrestrial Three-Dimensional Laser Scanning Systems for Highway Applications

2009 ◽  
Vol 2098 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Jagannath Hiremagalur ◽  
Kin S. Yen ◽  
Ty A. Lasky ◽  
Bahram Ravani
Keyword(s):  
Performance Evaluation ◽  
Laser Scanning ◽  
Three Dimensional ◽  
And Performance ◽  
Scanning Systems

Numerical Investigation of the 3D Flow Field in a Steam Turbine Axial Exhaust Diffuser: Comparison With Experimental Data and Performance Evaluation

2013 ◽  
Author(s):  
Federico Daccà ◽  
Claudio Canelli ◽  
Stefano Cecchi
Keyword(s):  
Experimental Data ◽  
Performance Evaluation ◽  
Flow Field ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Measured Data ◽  
Accurate Performance ◽  
And Performance ◽  
Lp Turbine ◽  
Actual Geometry

The purpose of this paper is to present a numerical analysis carried out for the performance evaluation of the axial exhaust diffuser of a LP steam turbine. A set of measured data in an actual real scale steam turbine is available for direct comparison. The three dimensional exhaust flow in a LP steam turbine provided with a 48″ LSB is numerically investigated in different real working conditions by means of 3D CFD analysis. A detailed 3D model of the actual geometry is used in order to catch the highly 3D features of the flow field, avoiding the use of numerical periodicity conditions. Boundary conditions are derived both from experimental data and from specific validated 3D simulations of the main flow of the entire LP turbine section from front stages up to the LSN. The comparison with measured data allows to validate the performed CFD simulations and to provide a reliable complete performance curve of the exhaust diffuser geometry coupled with the 48″ LSB design. An important outcome of the work consists also in a generalized method for accurate performance evaluation of axial diffusers.

scholarly journals Methodology for GD&T verification in an innovative benchmark part for contactless scanning systems

2020 ◽  
Vol 48 (4) ◽  
pp. 899-907
Author(s):  
Vimal Pathak ◽  
Ashish Srivastava ◽  
Sumit Gupta
Keyword(s):  
Performance Evaluation ◽  
Laser Scanning ◽  
Industrial Applications ◽  
Scanning System ◽  
Alignment Method ◽  
Engineering Software ◽  
Innovative Method ◽  
Contactless System ◽  
Geometrical Dimensioning And Tolerancing ◽  
Scanning Systems

This paper presents an innovative method to investigate the accuracy and capability of contactless laser scanning systems in terms of geometrical dimensioning and tolerancing (GD&T) control. The current work proposes a standard benchmark part with typical features conforming to different families of GD&T. The benchmark part designed consists of various canonical features widely used in an engineering and industrial applications. Further, the adopted approach includes the methodology for comparison of geometry using a common alignment method for contactless scanning system and a CMM. In addition, proposal of different scanning orientation methods for contactless system is also realized. Surface reconstruction of the benchmark model is achieved using different reverse engineering software, and results are analyzed to study the correlation between different geometries of contact and contactless system. Considering the contact based measurement as a reference, different models developed were analyzed and compared in terms of geometrical and dimensional tolerance. The proposal of standard benchmark part and methodology for GD&T verification will provide a simple and effective way of performance evaluation for various contactless laser-scanning systems in terms of deviations.

Development and performance evaluation of a three-dimensional clinostat synchronized heavy-ion irradiation system

2017 ◽  
Vol 12 ◽  
pp. 51-60 ◽  
Author(s):  
Hiroko Ikeda ◽  
Hikaru Souda ◽  
Anggraeini Puspitasari ◽  
Kathryn D. Held ◽  
Jun Hidema ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Ion Irradiation ◽  
Three Dimensional ◽  
Heavy Ion ◽  
Irradiation System ◽  
Heavy Ion Irradiation ◽  
And Performance

Study on the Management Performance Evaluation Model of Water Conservancy Agent Construction Project Based on Maturity and SCP Model

2014 ◽  
Vol 584-586 ◽  
pp. 2282-2285
Author(s):  
Xi Deng ◽  
Ping Gao ◽  
Jia Chen
Keyword(s):  
Performance Evaluation ◽  
Evaluation Model ◽  
Construction Project ◽  
Three Dimensional ◽  
Evaluation Index System ◽  
Management Performance ◽  
Performance Evaluation Model ◽  
Performance Evaluation Index ◽  
Water Conservancy ◽  
And Performance

During the next National Twelfth Five-Year Plan period, more and more water conservancy projects will be used agent construction mode in our country. The research of the management performance evaluation model for water conservancy is significant in improving the agent construction system both in theory and in practice. Considering the characteristics of the water conservancy project, a conceptual model of management performance is established, including agent construction structure and agent construction conduct. And a three-dimensional management performance evaluation model of water conservancy agent construction project is constructed based on the SCP (Structure-Conduct-Performance) analysis paradigm. Through literature review and questionnaire survey, this paper further refined evaluation dimension. Finally, a comprehensive and practical performance evaluation index system which consists of the 13 first-class, 39 second-class indexes is established. Thus, lay solid foundation for the performance evaluation and performance improvement.

scholarly journals A MARKER-FREE CALIBRATION METHOD FOR MOBILE LASER SCANNING POINT CLOUDS CORRECTION

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 347-354
Author(s):  
B. Yang ◽  
Y. Li ◽  
X. Zou ◽  
Z. Dong
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Calibration Method ◽  
Global Alignment ◽  
High Definition ◽  
Marker Free ◽  
Adjacent Segments ◽  
Scanning Systems ◽  
Coarse To Fine

Abstract. Mobile laser scanning systems (MLS) have been widely used in collecting three-dimensional point clouds for many applications, such as 3D mapping, road facilities inventory and high definition map. Although MLS is calibrated accurately to obtain precise locations of point clouds, it is still challenging to obtain precise locations of point clouds in the areas of GPS signal denied or narrow streets with high dense buildings, resulting in uneven position deviations of point clouds between the overlapping trajectory areas. In this paper, a marker-free calibration method is proposed to solve the above problems. The proposed method firstly partitions the trajectory into segments according to the error distribution while collecting the point clouds. Secondly, the features in each overlapped area are extracted and a kind of Locally Aggregated Descriptors are built for the matching. Thirdly, a coarse-to-fine pairwise point clouds alignment is applied on the overlapping areas. Finally, the global alignment of point clouds is fulfilled with minimizing the position deviations between the overlapping areas and the adjacent segments. The proposed method has been used to correct the point clouds from several different MLSs. Experiments show that this method automatically locates and corrects the uneven position deviations in terms of good robustness and efficiencies. Besides, it proves that the proposed method is also an easy-to-use tool for the automatic correction of MLS point clouds position and boresights.

3D Laser Scanner Techniques

2011 ◽  
pp. 500-527
Author(s):  
Mercedes Farjas ◽  
Jesús Martinez-Frias ◽  
Jose María Hierro
Keyword(s):  
Morphological Study ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanner ◽  
3D Laser Scanning ◽  
The Subject ◽  
First Time ◽  
Non Destructive ◽  
Arbitrary Objects ◽  
Scanning Systems

The use of 3D scanning systems for acquiring and analyzing the external shape features of arbitrary objects has different applications in different cultural, scientific, and technological fields. In this work, 3D laser scanning techniques are used, for the first time, to our knowledge, as a novel and non-destructive application for the morphological study of meteorite impact rocks. The subject of the study was a rock displaying impact textures and associated with the Karikkoselkä impact crater (Finland) (Lehtinen et al. 1996). This methodology permitted: (1) a computerized three-dimensional modelling to be carried out on the bulk impact-related rock; (2) other more specific characterizations to be performed, such as detailed topographic studies of its surface impact features; (3) some physical properties of the rock to be determined (volume); (4) the shatter cone impact texture to be completed with a realistic estimation of its convergence angle; and (5) a broad demonstration of the significance and effectiveness of 3D laser scanning techniques as a complementary tool for the study of this type of meteoritic impact-related rocks.

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