1,720,969 research outputs found
AdvanCT EURAMET project, Southampton XCT scan data, Sphere sample, fast scan
No full textTowsyfyan, Hossein; Biguri, Ander; Deyhle, Hans; Lindroos, Reuben
AdvanCT EURAMET project, Southampton XCT scan data, Double ruby sphere sample, fast scan
20181107_HUTCH_2074_HD_6mm_ideal_1fpp_2W
6mm ruby spheres, touching
Data acquisition system: Custom Nikon metrology custom x-ray tomography system
Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size.
Nikon 225kVp reflection target microfocus source
134ms exposure per frame, 90kVp, 22 μA, 3143 projections, 7 minutes, no shuttling, continuous motion scanning mode
S2O: 27.8778991699219
S2D: 799.6818
Funded through EURAMET EMPIR Joint Research Project AdvanCT - 17IND08 </span
AdvanCT EURAMET project, Southampton XCT scan data, EMPA sample, fast scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, EMPA sample, fast scan 20190314_HUTCH_2220_HT_EMPA_450fastfilter_003 EMPA step cylinder phantom - aluminium Data acquisition system: Custom Nikon metrology custom x-ray tomography system Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size. Nikon 450kVp reflection target microfocus source 250ms exposure per frame, 390kVp, 242 μA, 3143 projections, 13 minutes, 8mm copper filter, no shuttling, continious scanning mode S2O: 652.500579833984 S2D: 107.011</span
AdvanCT EURAMET project, Southampton XCT scan data, NPL sample, slow scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, NPL sample, slow scan 20190312_HUTCH_2220_NPL_Long225_001 NPL phantom - aluminium Data acquisition system: Custom Nikon metrology custom x-ray tomography system Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size. Nikon 225kVp reflection target microfocus source 134ms exposure per frame averaged over 16 frames, 160kVp, 142 μA, 3143 projections, 185 minutes, shuttling, stop start scanning mode S2O: 255.7822265625 S2D: 895.7499</span
AdvanCT EURAMET project, Southampton XCT scan data, Sphere sample, slow scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, Double ruby sphere sample, slow scan
20181107_HUTCH_2074_HD_6mm_ideal_1fpp
6mm ruby spheres, touching
Data acquisition system: Custom Nikon metrology custom x-ray tomography system
Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size.
Nikon 225kVp reflection target microfocus source
134ms exposure per frame, 90kVp, 155 μA, 3143 projections, 7 minutes, no shuttling, continuous motion scanning mode
S2O: 27.8778991699219
S2D: 799.6818</span
AdvanCT EURAMET project, Southampton XCT scan data, NPL sample, fast scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, NPL sample, slow scan 20190312_HUTCH_2220_NPL_Fast225_002 NPL phantom - aluminium Data acquisition system: Custom Nikon metrology custom x-ray tomography system Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size. Nikon 225kVp reflection target microfocus source 134ms exposure per frame, 90kVp, 113 μA, 3143 projections, 7 minutes, no shuttling, continuous scanning mode S2O: 255.781982421875 S2D: 895.7496</span
AdvanCT EURAMET project, Southampton XCT scan data, PTB sample, fast scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, PTB sample, fast scan 20190312_HUTCH_2220_HT_PTB_fast_002 PTB hole plate (6mm) - aluminium Data acquisition system: Custom Nikon metrology custom x-ray tomography system Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size. Nikon 225kVp reflection target microfocus source 134ms exposure per frame, 120kVp, 83 μA, 3143 projections, 7 minutes, no shuttling, continious scanning mode S2O: 23.5411643981934 S2D: 670.0555</span
AdvanCT EURAMET project, Southampton XCT scan data, EMPA sample, slow scan
No full textAdvanCT EURAMET project, Southampton XCT scan data, EMPA sample, slow scan 20190315_HUTCH_2220_HT_EMPA_450longfilter_002 EMPA step cylinder phantom - aluminium Data acquisition system: Custom Nikon metrology custom x-ray tomography system Detector: PerkinElmer XRD 1621 CN3 – HS, 2000x2000 pixels, 200 μm2 pixel size. Nikon 450kVp reflection target microfocus source 708ms exposure per frame averaged over 16 frames, 390kVp, 242 μA, 3143 projections, 760 minutes, 8mm copper filter, shuttling, stop start scanning mode S2O: 652.500579833984 S2D: 1107.011</span
Effects of fast X-Ray cone-beam tomographic measurement on dimensional metrology
Get PDFX-ray computed tomography (XCT) is increasingly used for dimensional metrology, where it can offer accurate measurements of internal features that are not accessible with other techniques. However, XCT scanning can be relatively slow, which often prevents routine uptake for many applications. This paper explores the feasibility of improving the speed of XCT measurements whilst maintaining the quality of the dimensional measurements derived from reconstructed volumes. In particular, we compare two approaches to fast XCT acquisition, the use of fewer XCT projections as well as the use of shortened x-ray exposure times for each projection. The study shows that the additional Poisson noise produced by reducing the exposure for each projection has significantly less impact on dimensional measurements compared to the artefacts associated with strategies that take fewer projection images, leading to about half the measurement error variability. Advanced reconstruction algorithms such as the conjugate gradient least squares method or total variation constrained approaches, are shown to allow further improvements in measurement speed, though this can come at the cost of increased measurement bias (e.g. 2.8 % increase in relative error in one example) and variance (e.g. 25 % in the same example)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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