643 research outputs found
Causes of Error for Turbine Radial Palette Measurement
No full textThis paper describes the project of an optical measurement system, an evolution of the system currently installed on the lathe for turbine palettes refinement in Ansaldo Energie, developed by the Politecnico di Milano. This article analyzes the most significant causes of errors found in designing an optical measurement system, proposing improvements that can optimize the system, both in terms of performance and reliability. The idea behind this work is to develop a system that can measure with an accuracy of 10m the difference of length of palettes of a turbine stadium in real time, while the turbine is turning on a refinement lathe
Interferometric instrument for thickness measurement on blown films
No full textReal-time measurement of plastic film thickness during production is extremely important to guarantee planarity of the final film. Standard techniques are based on capacitive measurements, in close contact with the film. These techniques require continuous calibration and temperature compensation, while their contact can damage the film. Different optical contactless techniques are described in literature, but none has found application to real production, due to the strong vibration of the films. We propose a new structure of low-coherence fiber interferometer able to measure blown film thickness during productions. The novel fiber-optic setup is a cross between an autocorrelator and a white light interferometer, taking the advantages of both approaches. View Full-Text
Optical sensor for extracorporeal blood flow measurement
No full textThis work describes the design and realization of an optical sensor for measuring extracorporeal blood flow. The instrument is realized by means of a self-mixing interferometer and a dedicated data elaboration system, developed by means of a numerical simulator of the blood optical scattering
Diagnosi precoce del cancro del polmone in lavoratori esposti a cancerogeni
No full textFollowing the publication of results of NLST (National Lung Screening Trial, USA) and ELCAP (Early Lung Cancer Action Project, USA), lung cancer screening with low-dose computed tomography (LDCT) in high-risk subjects has been recommended in North-America. Conversely, the European Community has been waiting for further evidence. The recently concluded Dutch-Belgian Lung Cancer Screening trial (NELSON) confirmed the efficacy of LDCT screening in reducing lung cancer mortality. Two recent studies in the USA and Italy showed positive results in occupational settings among workers formerly exposed to asbestos. The available evidence seems to suggest the need to implement lung cancer screening programs among heavy smokers and workers substantively exposed to occupational carcinogens also in Europe, following common, standardized procedures, as indicated in a recent European position statement
Self-Mixing Laser Doppler Spectra of Extracorporeal Blood Flow: A Theoretical and Experimental Study
No full textTheoretical and experimental analysis of the spectral characteristics of the signal acquired from self-mixing laser Doppler of extracorporeal blood flow is presented. The theoretical spectrum of the predetected signal is calculated in the single scattering approximation and assuming a parabolic velocity profile in the duct. The resulting signal is mixed in a diode laser cavity to generate the sensor output. Theoretical predictions are verified by measurements performed on blood and phantoms flowing in an extracorporeal circulation system
Self-mixing laser Doppler: a model for extracorporeal blood flow measurement
No full textA theory is developed to study the spectral characteristics of the signal acquired from self-mixing laser Doppler of extracorporeal blood flow. Doppler shifts is generated by erythrocyte cells interacting with the illumination photons. The resulting signal is mixed in the laser cavity to generate the sensor output. In order to predict analytically the spectrum of the Doppler signal, is assumed:week optical feedback, single scattering event and a Gaussian illumination beam. Predictions are verified by measurements on blood in extracorporeal circulation system
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