Characterisation of the topography of metal additive surface features with different measurement technologies

The challenges of measuring the surface topography of metallic surfaces produced by additive manufacturing are investigated. The differences between measurements made using various optical and non-optical technologies, including confocal and focus-variation microscopy, coherence scanning interferometry and x-ray computed tomography, are examined. As opposed to concentrating on differences which may arise through computing surface texture parameters from measured topography datasets, a comparative analysis is performed focussing on investigation of the quality of the topographic reconstruction of a series of surface features. The investigation is carried out by considering the typical surface features of a metal powder-bed fusion process: weld tracks, weld ripples, attached particles and surface recesses. Results show that no single measurement technology provides a completely reliable rendition of the topographic features that characterise the metal powder-bed fusion process. However, through analysis of measurement discrepancies, light can be shed on where instruments are more susceptible to error, and why differences between measurements occur. The results presented in this work increase the understanding of the behaviour and performance of areal topography measurement, and thus promote the development of improved surface characterisation pipelines

Internal surface measurement of metal powder bed fusion parts

Recent advances in X-ray computed tomography (XCT) have allowed for measurement resolutions approaching the point where XCT can be used for measuring surface topography. These advances make XCT appealing for measuring hard-to-reach or internal surfaces, such as those often present in additively manufactured parts. To demonstrate the feasibility and potential of XCT for topography measurement, topography datasets obtained using two XCT systems are compared to those acquired using coherence scanning interferometry and focus variation microscopy. A hollow Ti6Al4V part produced by laser powder bed fusion is used as a measurement artefact. The artefact comprises two component halves that can be separated to expose the internal surfaces. Measured surface datasets are accurately aligned and similarly cropped, and compared by various qualitative and quantitative means, including the computation of ISO 25178-2 areal surface texture parameters, commonly used in part quality assessment. Results show that XCT can non-destructively provide surface information comparable with more conventional surface measurement technologies, thus representing a viable alternative to more conventional measurement, particularly appealing for hard-to-reach and internal surfaces

Investigation of image distortion due to MCP electronic readout misalignment and correction via customized GUI application

The MCP-based neutron counting detector is a novel device that allows high spatial resolution and time-resolved neutron radiography and tomography with epithermal, thermal and cold neutrons. Time resolution is possible by the high readout speeds of ∼ 1200 frames/sec, allowing high resolution event counting with relatively high rates without spatial resolution degradation due to event overlaps. The electronic readout is based on a Timepix sensor, a CMOS pixel readout chip developed at CERN. Currently, a geometry of a quad Timepix detector is used with an active format of 28 × 28 mm2 limited by the size of the Timepix quad (2 × 2 chips) readout. Measurements of a set of high-precision micrometers test samples have been performed at the Imaging and Materials Science & Engineering (IMAT) beamline operating at the ISIS spallation neutron source (U.K.). The aim of these experiments was the full characterization of the chip misalignment and of the gaps between each pad in the quad Timepix sensor. Such misalignment causes distortions of the recorded shape of the sample analyzed. We present in this work a post-processing image procedure that considers and corrects these effects. Results of the correction will be discussed and the efficacy of this method evaluated

User, Customer and Consumer Experience: Highlighting the Heterogeneity in the Literature

The notion of experience has gained in popularity both in management and in computer science. To assess the quality of an information system, specialists in human-computer interaction are now referring to the user experience. On the marketing side, the concept of experience has also become key to describe the relationship between an individual and a brand. Several streams of research exist, some privileging the notion of customer experience and others of consumer experience. However, the multiplication of those works also created fragmentation and theoretical heterogeneity, as emerged through our analyses. This situation is particularly noxious to the communication between the disciplines of human-computer interaction and marketing, becoming more and more necessary. In order to promote this multidisciplinary communication, we clearly define and differentiate the constructs of experience. We also highlight the current heterogeneity in the literature through a systematic literature review and we end by formulating some suggestions to researchers and practitioners. This work contributes to a better communication between the disciplines of human-computer interaction and marketing, and more particularly to the unification of the constructs of experience

The Mexican amber anole, Anolis electrum

Castañeda, María Del Rosario, Sherratt, Emma, Losos, Jonathan B. (2014): The Mexican amber anole, Anolis electrum, within a phylogenetic context: implications for the origins of Caribbean anoles. Zoological Journal of the Linnean Society 172 (1): 133-144, DOI: 10.1111/zoj.12159, URL: http://dx.doi.org/10.1111/zoj.1215