Multiple-sensor integration for efficient reverse engineering of geometry

This paper describes a multi-sensor measuring system for reverse engineering applications. A sphere-plate artefact is developed for data unification of the hybrid system. With the coordinate data acquired using the optical system, intelligent feature recognition and segmentation algorithms can be applied to extract the global surface information of the object. The coordinate measuring machine (CMM) is used to re-measure the geometric features with a small amount of sampling points and the obtained information can be subsequently used to compensate the point data patches which are measured by optical system. Then the optimized point data can be exploited for accurate reverse engineering of CAD model. The limitations of each measurement system are compensated by the other. Experimental results validate the accuracy and effectiveness of this data optimization approach

Hybrid Software Development Approaches in Practice: A European Perspective

Agile and traditional development approaches are used in combination in todays software development. To improve the understanding and to provide better guidance for selecting appropriate development approaches, it is important to analyze such combinations in practice. Results obtained from an online survey strongly confirm that hybrid development approaches are widely used in industry. Our results show that hybrid development approaches: (i) have become reality for nearly all companies; (ii) are applied to specific projects even in the presence of company-wide policies for process usage; (iii) are neither planned nor designed but emerge from the evolution of different work practices; and, (iv) are consistently used regardless of company size or industry secto

Validation of phosphor thermometry for industrial surface temperature measurements

Surface temperature measurements are required by the aerospace and automotive industries to guarantee high-quality products and optimize production processes. Accurate and reliable measurement of surface temperature is very challenging in an industrial environment. Surface contact probes are widely used but poorly characterized, while non-contact infrared thermometry is severely hampered by the unknown emissivity of the surface and by problems caused by stray radiation from the background. An alternative approach to the above techniques is phosphor thermometry, used here in a hybrid contact/non-contact approach. In this work, the development of a lifetime-based phosphor thermometer, its application to industrial surface temperature measurement and its validation are reported in a metrologically sound manner. The phosphor thermometer was initially calibrated by contact on a reference calibrator system at the Istituto Nazionale di Ricerca Metrologica to provide SI traceability to the measurements at the industrial level; the system was later validated by exploiting a metal phase-change method. The robustness of the approach against a strong radiative background was also investigated. A comprehensive uncertainty analysis was carried out, resulting in an expanded uncertainty (k  =  2) lower than 1.4 °C over the temperature range from the ambient to 450 °C. The phosphor-based thermometer was then tested at industrial manufacturing premises to measure the surface temperature of aluminium alloy billets during the pre-heating phase before forging. The phosphor-based approach was compared with radiation and contact thermometry in both static and dynamic measurement conditions. The experimental results proved that phosphor thermometry, besides being a valid alternative to conventional techniques, may offer better performance in an industrial setting

Rapid Prototyping of PEM Fuel Cell Bi-Polar Plates using 3D Printing and Thermal Spray Deposition

This article presents the results of exploratory research on novel methods for the fabrication of functional, metallic, gas flow, bi polar plates (BPP) for use in proton exchange membrane fuel cells (PEMFC). Low cost, high speed, additive manufacturing methods that combine 3D printing (3DP) and thermal spray (TS) technologies are described. Functional flow plates were manufactured by creating 3DP patterns and then depositing, and releasing, dense metals with TS methods. The new method yields dense metal plates, with interesting options for material choices and complex designs.Mechanical Engineerin

Solar-thermal and hybrid photovoltaic-thermal systems for renewable heating

Grantham Briefing Papers analyse climate change and environmental research linked to work at Imperial College London, setting it in the context of national and international policy and the future research agenda. This paper and other Grantham publications are available from: www.imperial.ac.uk/grantham/publicationsThis paper looks at the barriers and opportunities for the mass deployment of solar-thermal technologies and offers a vision for the future of solar-thermal systems. HEADLINES: -Heat constitutes about half of total global energy demand. Solar heat offers key advantages over other renewable sources for meeting this demand through distributed, integrated systems. -Solar heat is a mature sustainable energy technology capable of mass deployment. There is significant scope for increasing the installed solar heat capacity in Europe. -Only a few European countries are close to reaching the EU target of 1 m2 of solar-thermal installations per person. -One key challenge for the further development of the solar-thermal market arises from issues related to the intermittency of the solar resource, and the requirement for storage and/or backup systems. The former increases investment costs and limits adaptability. -An analysis of EU countries with good market development, suggests that obligation schemes are the best policy option for maximising installations. These do not present a direct cost to the public budget, and determine the growth of the local industry in the long term. -Solar-thermal collectors can be combined with photovoltaic (PV) modules to produce hybrid PV-thermal (PV-T) collectors. These can deliver both heat and electricity simultaneously from the same installed area and at a higher overall efficiency compared to individual solar-thermal and PV panels installed separately. --Hybrid PV-T technology provides a particularly promising solution when roof space is limited or when heat and electricity are required at the same time.Preprin

Status of a DEPFET pixel system for the ILC vertex detector

We have developed a prototype system for the ILC vertex detector based on DEPFET pixels. The system operates a 128x64 matrix (with ~35x25 square micron large pixels) and uses two dedicated microchips, the SWITCHER II chip for matrix steering and the CURO II chip for readout. The system development has been driven by the final ILC requirements which above all demand a detector thinned to 50 micron and a row wise read out with line rates of 20MHz and more. The targeted noise performance for the DEPFET technology is in the range of ENC=100 e-. The functionality of the system has been demonstrated using different radioactive sources in an energy range from 6 to 40keV. In recent test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120 has been achieved with present sensors being 450 micron thick. For improved DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40 is expected.Comment: Invited poster at the International Symposium on the Development of Detectors for Particle, AstroParticle and Synchrotron Radiation Experiments, Stanford CA (SNIC06) 6 pages, 12 eps figure

A review of advances in pixel detectors for experiments with high rate and radiation

The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy