The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Lander Barrenetxea - One of the best experts on this subject based on the ideXlab platform.
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Framework for verification of Positional Tolerances with a 3D non-contact measurement method
International Journal on Interactive Design and Manufacturing (IJIDeM), 2016Co-Authors: Rikardo Minguez, Agustin Arias, Olatz Etxaniz, Eneko Solaberrieta, Lander BarrenetxeaAbstract:New methods of data acquisition such as 3D scanners have become increasingly necessary for the verification of the geometric dimensioning and tolerancing (GD&T) specifications in the manufacture of industrial parts. This paper proposes a method for the verification of a Positional Tolerance in two cylindrical features in an industrial part digitized using a 3D non-contact scanner. Apart from enabling an adequate quantification of the obtained results, this method also permits the displaying of different ways of visualizing the results. The Tolerance zone within which the used scanner carries out the analysis was measured and quantified. Some aspects taken into consideration were the geometric quality of the piece and the repeatability, the reproducibility and the uncertainty of the digital process, which comprises the acquisition and processing of the data. This research work concludes that the digital method presented hereby, with its corresponding virtual inspection, is valid for the verification of Positional Tolerances, even when it is required to maintain the GD&T specification regardless of the feature size. In addition, this article raises the discussion over the best way to compute the traditional datum referencing rules to the new data acquisition methods.
Ya-wen Wang - One of the best experts on this subject based on the ideXlab platform.
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Stereospecific Synthesis of Tetrahydronaphtho[2,3‑ b ]furans Enabled by a Nickel-Promoted Tandem Reductive Cyclization
Organic Letters, 2016Co-Authors: Yu Peng, Jian Xiao, Shu-ming Duan, Li Ren, Yongliang Shao, Ya-wen WangAbstract:A Ni-mediated cascade to a stereoselective synthesis of trans-tetrahydronaphtho[2,3-b]furans is efficiently achieved for the first time. The mild reductive system can be easily generated from inexpensive and air-stable materials and shows a broad Positional Tolerance of substituents that were previously difficult or impossible to access by other methods. Facile syntheses toward new analogues of therapeutic agents (iso)deoxypodophyllotoxin are also reported. In addition, the inherent substrate control is disclosed for the observed unique stereoselectivities during cyclizations.
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Stereospecific Synthesis of Tetrahydronaphtho[2,3‑b]furans Enabled by a Nickel-Promoted Tandem Reductive Cyclization
2016Co-Authors: Yu Peng, Jian Xiao, Shu-ming Duan, Li Ren, Yongliang Shao, Ya-wen WangAbstract:A Ni-mediated cascade to a stereoselective synthesis of trans-tetrahydronaphtho[2,3-b]furans is efficiently achieved for the first time. The mild reductive system can be easily generated from inexpensive and air-stable materials and shows a broad Positional Tolerance of substituents that were previously difficult or impossible to access by other methods. Facile syntheses toward new analogues of therapeutic agents (iso)deoxypodophyllotoxin are also reported. In addition, the inherent substrate control is disclosed for the observed unique stereoselectivities during cyclizations
R.c. Wimpory - One of the best experts on this subject based on the ideXlab platform.
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Development of procedures for the measurement of residual stress by neutron diffraction
Applied Physics A, 2002Co-Authors: G.a. Webster, R.c. WimporyAbstract:Neutron diffraction is a non-destructive method for determining residual stresses in crystalline materials. It is a relatively new technique and no standard is currently available for making these measurements. This paper gives the background to research that has been carried out to develop a standard. It outlines the main findings and indicates the precautions that are required to achieve accurate positioning and alignment of specimens (and components) in a neutron beam and the analysis required to obtain reliable results. It also shows that special attention is needed in dealing with near-surface measurements because of surface aberration. It is demonstrated that, provided the recommended procedures are followed, a Positional Tolerance of ±0.1 mm can be achieved with an accuracy in strain of ∼10^-4, to give a resolution in residual stress of ∼7 to 20 MPa in most materials of practical interest.
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Draft Standard for the Measurement of Residual Stresses by Neutron Diffraction
Recent Advances in Experimental Mechanics, 2002Co-Authors: G.a. Webster, A. G. Youtsos, Carsten Ohms, R.c. WimporyAbstract:Residual stresses can have important consequences for the load carrying capacity and safety of engineering components. Neutron diffraction is a non-destructive method for determining residual stresses in crystalline materials. It is a relatively new technique and no standard is currently available for making these measurements. This paper gives the background to research that has been carried out to develop a standard. It outlines the main findings and indicates the precautions that are required to achieve accurate positioning and alignment of specimens (and components) in a neutron beam and the analysis required to obtain reliable results. It also shows that special attention is needed in dealing with near-surface measurements because of surface aberration. It is demonstrated that, provided the recommended procedures are followed, a Positional Tolerance of ±0.1mm can be achieved with an accuracy in strain of ±10−4 to give a resolution in residual stress of ±7 to 20 MPa in most materials of practical interest.
Rikardo Minguez - One of the best experts on this subject based on the ideXlab platform.
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Framework for verification of Positional Tolerances with a 3D non-contact measurement method
International Journal on Interactive Design and Manufacturing (IJIDeM), 2016Co-Authors: Rikardo Minguez, Agustin Arias, Olatz Etxaniz, Eneko Solaberrieta, Lander BarrenetxeaAbstract:New methods of data acquisition such as 3D scanners have become increasingly necessary for the verification of the geometric dimensioning and tolerancing (GD&T) specifications in the manufacture of industrial parts. This paper proposes a method for the verification of a Positional Tolerance in two cylindrical features in an industrial part digitized using a 3D non-contact scanner. Apart from enabling an adequate quantification of the obtained results, this method also permits the displaying of different ways of visualizing the results. The Tolerance zone within which the used scanner carries out the analysis was measured and quantified. Some aspects taken into consideration were the geometric quality of the piece and the repeatability, the reproducibility and the uncertainty of the digital process, which comprises the acquisition and processing of the data. This research work concludes that the digital method presented hereby, with its corresponding virtual inspection, is valid for the verification of Positional Tolerances, even when it is required to maintain the GD&T specification regardless of the feature size. In addition, this article raises the discussion over the best way to compute the traditional datum referencing rules to the new data acquisition methods.
Yu Peng - One of the best experts on this subject based on the ideXlab platform.
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Stereospecific Synthesis of Tetrahydronaphtho[2,3‑ b ]furans Enabled by a Nickel-Promoted Tandem Reductive Cyclization
Organic Letters, 2016Co-Authors: Yu Peng, Jian Xiao, Shu-ming Duan, Li Ren, Yongliang Shao, Ya-wen WangAbstract:A Ni-mediated cascade to a stereoselective synthesis of trans-tetrahydronaphtho[2,3-b]furans is efficiently achieved for the first time. The mild reductive system can be easily generated from inexpensive and air-stable materials and shows a broad Positional Tolerance of substituents that were previously difficult or impossible to access by other methods. Facile syntheses toward new analogues of therapeutic agents (iso)deoxypodophyllotoxin are also reported. In addition, the inherent substrate control is disclosed for the observed unique stereoselectivities during cyclizations.
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Stereospecific Synthesis of Tetrahydronaphtho[2,3‑b]furans Enabled by a Nickel-Promoted Tandem Reductive Cyclization
2016Co-Authors: Yu Peng, Jian Xiao, Shu-ming Duan, Li Ren, Yongliang Shao, Ya-wen WangAbstract:A Ni-mediated cascade to a stereoselective synthesis of trans-tetrahydronaphtho[2,3-b]furans is efficiently achieved for the first time. The mild reductive system can be easily generated from inexpensive and air-stable materials and shows a broad Positional Tolerance of substituents that were previously difficult or impossible to access by other methods. Facile syntheses toward new analogues of therapeutic agents (iso)deoxypodophyllotoxin are also reported. In addition, the inherent substrate control is disclosed for the observed unique stereoselectivities during cyclizations