1,721,392 research outputs found
Metrological assessment of a robotic total station for use in post-earthquake emergency conditions
No full textThe paper provides synthetic indications regarding the measuring performances of procedures for using a robotic total station (RTS) in emergency situations, such as the survey of the structural conditions of buildings and the assessment of the safety level for rescue operations after the occurrence of an earthquake. Particular attention is paid to operative aspects that could impact on the performance of the system in this situation; specifically considered is the effect of the layout of the measurement setup and of the number of monitoring points, depending on the geometry of the site and of the considered buildings, because the criticality of emergency conditions imposes geometrical solutions which are far from having optimal solutions. The analysis is carried out with reference to two different buildings, which have different characteristics from the point of view of height and distance from the instrument, and that implies different geometrical constraints for the instrument during the acquisition of the monitoring points. The methodology allows the evaluation of the repeatability, reproducibility, and detection limit of a RTS, in field conditions, referring to a 1-year observation period, with reference to different quantities, like positions of the monitoring points and the inclination of walls and façades. In particular, the analysis of the geometrical characteristics of reduced configurations of the monitoring points has highlighted interesting aspects in view of defining a simplified procedure, which is also suitable for speeding up the acquisition of reliable data in emergency conditions
Omelia copta attribuita a Demetrio di Antiochia. Sul Natale e Maria Vergine - recenzja
Full text linkRecenzja: Krzysztof Modras, Omelia copta attribuita a Demetrio di Antiochia, Sul Natale e Maria Vergine, Roma 1995, 241 s
Calibration Uncertainty of Three-Axis Low Frequency Accelerometers: Test Rig and Procedure Aspects
No full textIn this paper a methodology is described
concerning the calibration of three-axis low-cost
accelerometers in the 0 to 10 Hz frequency range,
to be used for evaluation of existing civil
infrastructures. Particular attention is paid to the
evaluation of the calibration uncertainty with
reference to both static and dynamic operating
conditions and to the aspects specifically related
to the test bench and to the calibration procedure.
These aspects mainly concern the test bench
behavior in realizing the requested motion law,
the choosing of the reference for calibration and
the data processing techniques.
The obtained results show that a great
improvement of the low cost accelerometers’
metrological characterization could be achieved
according to the procedure described in this
paper; furthermore, interesting considerations
have been carried out with reference to the
evaluation of main and cross sensitivity of
accelerometers also in dynamic working
conditions
Validation of Methods for Optical Characterization of Wettability of Polymeric Films for Food Packaging
No full textAmethodology is described for the theoretical-experimental evaluation of themeasurement uncertainty of the polar and dispersive
components of the surface free energy (SFE) in polypropylene films; these parameters are related to the filmwettability of adhesives
and inks. The proposed method is based on the measurement by means of a vision system of the contact angles of liquid drops
deposited on the film itself, which allows for obtaining, through mathematical models drawn from the literature, the physical
quantities of interest.The effect of the principal influence parameters has been experimentally evaluated, and testing has allowed
the defining of the technical procedures readily transferable in the industry. The uncertainty assessment is interesting not only
to correctly evaluate experimental data but also to characterise the reproducibility of the effects of techniques for improving the
wettability of films, such as surface treatments
Tri-axial accelerometer calibration by means of a three-axis acceleration field for low-frequency vibrations,
No full textIn this paper a calibration procedure is described concerning the
experimental evaluation of both main and transverse sensitivities of tri-axial
accelerometers. A rotary test bench allows us to create a three-axis field of
acceleration, so that the matrix of main and transverse sensitivities can be
evaluated by a direct method. Uncertainty of the methodology is also
estimated. The procedure allows to correct on line transverse sensitivity
effects; it has been set up and validated on the same test bench. Finally, the
validity of the procedure has been tested for multi-axis accelerometers of
classical and innovative type. The proposed method appears to be useful for
calibration of tri-axial accelerometers, in particular for low-cost ones,
operating in the range of frequency of 0 -5 Hz
ORSADEM: a one dimension shallow water code for flood inundation modelling
No full textThis paper describes the software ORSADEM, which solves the one-dimensional (1-D) shallow water equations written in conservative form by numerical schemes suitable for the modelling of shocks and discontinuities generated by a dam break. Unlike the majority of the commercial software, ORSADEM automatically defines the model cross-sections based on the terrain digital elevation model (DEM) and automatically maps the flood prone areas solving the hydraulic equations. The flooded area is mapped using a new method congruent with the unidimensionality of the model. ORSADEM does not need any external platforms. The software has been developed by researchers of the Department of Civil and Architectural Engineering at University of Pavia and it is here presented applied to the case study of the Brembo River
Network of MEMS sensors for condition monitoring of industrial systems: Accuracy assessment of features used for diagnosis
No full textThis paper analyses the effect of variability of metrological characteristics of a set of low-cost MEMS accelerometers on the calculation of typical features used in condition monitoring of automatic production lines. The knowledge of the contribution of the variability of sensor metrological characteristics to the final accuracy of features is expected to be interesting when networks of low-cost sensors are used or in cases the spread of their characteristics is high, due to a mass production without single calibration. The real variability of the sensor's characteristics has been experimentally evaluated according to a calibration of a set of 25 low-cost MEMS, carried out sensor by sensor. Digital sensitivity, signal-to-noise ratio and data rate variability of each sensor have been considered for analysis. Experimental data from an industrial test case has been processed comparing real data, by a high performance piezoelectric accelerometer, and modified ones, taking into account the variability of the above characteristics of MEMS. The results show which features are more affected and which characteristics of MEMS are more influencing the features themselves
Design and set up of an automatic device for on-line measurement of Cr(VI) concentration in water, based on a fiber optic probe
No full textAn experimental apparatus is described for automatic measurement of Cr(VI) concentration in water. Measuring section is a miniaturized fiber optic probe.
Experimental results are discussed with reference to both manual and automatic working conditions in order to get informations on performance to be achieved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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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