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Innovative Humidity Sensitive Electrical Properties of Sol-Gel Processed Ceramic Thin Films
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The use of electrochemical noise analysis on corroding systems
No full textThis paper gives an overview of the use of Electrochemical Noise (EN) for corrosion studying and monitoring. Since the quality and reliability of noise data are affected by a number of acquisition parameters, such as sampling interval, sampling duration, D.C. trend and instrumental noise, some experimental and practical aspects were discussed. The use of statistical parameters such as standard deviation, Pit Index and/or Localization Index and Noise Resistance to analyze noise data of corroding systems were examined. Many experimental applications of Electrochemical Noise Measurements on different metals and alloys were given. EN data have been compared with traditional electrochemical techniques. EN allowed to characterize the corrosion behavior of samples giving in some cases good quantitative estimation. The transposition of current and potential noise acquisition in the frequency domain (by Fast Fourier Transform and/or Maximum Entropy Method), gave further information on corrosion mechanism and in particular permitted to identify the type of corrosion. Finally the use of Discriminant Analysis permitted to deduce the best sampling frequency and sampling duration for EN acquisition, able to discriminate between two different situations
Caratterizzazione di leghe Sn-In-Cu per saldatura
No full textIn questo lavoro vengono presentati i risultati delle prove di corrosione e delle prove di trazione condotte su tre tipologie di campioni di lega per saldatura 75Sn-24In-1Cu. La prima serie è una “as cast” ovvero la lega come uscita dal getto di fusione, mentre sulle altre due tipologie sono stati effettuati un processo di laminazione e un processo di laminazione seguito da una ricottura. I campioni sono stati sottoposti a prove di resistenza di corrosione in NaCl 3% ed effettuando misure di Spettroscopia di Impedenza (EIS) ed i dati sono stati analizzati mediante l’uso di circuiti equivalenti. Sono state realizzate prove di trazione semplice su tutte le tipologie di lega
Electrochemical noise for corrosion detection
No full textIn the last years, a growing interest on the use of Electrochemical Noise (EN) for corrosion studies may be detected in the main literature. As a result of this, several methods for analyzing noise data have been developed.
In this paper a review of the investigative possibilities offered by EN in the field of corrosion is given.
All the experimental data reported are from research projects developed in our laboratory where, for more than 15 years, EN has been applied to the solution of different corrosion problems and some dedicated software have been developed for EN data analysis (FFT-MEM, PSD slope detection, discriminant analysis). Much attention will be given to the use of statistical parameters and their significance in terms of corrosion behavior of the electrode.
Moreover, the experimental caution to use in order to have meaningful data will be highlighted
Sensore di umidità utilizzante un nuovo elemento sensibile ceramico in film sottile preparato per sol-gel.
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Sensore di umidità utilizzante un nuovo elemento sensibile di TiO2 drogata con alcali in film sottile preparato per sol-gel
No full textDiscrete Damage Modelling for Computer Aided Acoustic Emissions.
No full textThis chapter is conceived as an essay on modern multiscale discrete damage modelling,
providing a brief personal perspective about its foreseeable applications-implications for
structural health monitoring purposes. In particular, it is argued that this sort of damage
modelling could be potentially useful in damage detection by acoustic emissions (AE),
which is a class of non-destructive techniques (NDT) used to capture damage evolution in a
number of materials (e.g. from concrete systems such as bridges and beam elements to
composites in aircraft components and pressure equipments) and from a number of external
actions (e.g. sustained load, monotonic testing, fatigue, corrosion, etc.) (Biancolini & Brutti,
2006 ; Carpinteri & Lacidogna, 2008 ; Grosse & Ohtsu, 2008). With AE it is possible to “hear”
the microcracking phenomenon and characterize the location and magnitude of a single
microcrack (of size and “strength”1 beyond certain thresholds) acting as an acoustic source.
Hence, it is routinely possible to plot the released energy of each crack as a time series or to
map them over a 2D spatial domain by counting and locating individual acoustic events in
time. Yet the analysis of this type of output is not straightforward and major difficulties
exist, let alone sensitivity issues of equipment, material dependence, and other practical
issues. The scope of this discussion covers two issues of general interest:
1. the randomness of the AE signal,
2. the need for structure-property relations as companion to AE monitoring
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