Navigare nel WWW a scuola: ma per andare dove?

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LabTD: un laboratorio di tecnologie didattiche per docenti

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Low-cost electrochemical impedance spectroscopy system for corrosion monitoring of metallic antiquities and works of art

Electrochemical impedance spectroscopy (EIS) is recognized to be a powerful and noninvasive technique to test the integrity of protective coatings on memorials, but commercial EIS systems are rather costly though versatile devices. This paper describes a low cost and portable EIS system that is based on a compact digital signal processor (DSP) board and embeds the potentiostatic function so that it can be used without requiring an external potentiostat. The software that runs on the DSP is designed to analyze the electrochemical impedance only in a reduced frequency range in order to produce a simple corrosion alert result. The device is equipped with a digital interface and can be connected to a personal computer to carry out a complete frequency analysis and perform a more complex data processing

Exposure-Tolerant Imaging Solution forCultural Heritage Monitoring

This paper describes a simple and cheap solution specifically designed for monitoring the degradation of thin coatings employed for metal protection. The proposed solution employs a commercial photocamera and a frequency-domain-based approach that is capable of highlighting the surface uniformity changes due to initial corrosion. Even though the proposed solution is specifically designed to monitor the long-time performance of protective coatings employed for the restoration of silver artifacts, it can be successfully used also for assessing the conservation state of other ancient metallic works of art. The proposed solution is made tolerant to exposure changes by using a procedure for sensor nonlinearity identification and correction, does not require a precise lighting control, and employs only free open-source software, so that its overall cost is very low and can be used also by not specifically trained operator

Handheld-Impedance-Measurement System with seven-decade capability and potentiostatic function

This paper describes design and test of a new impedance-measurement system for nonlinear devices that exhibits a seven-decade range and works down to a frequency of 0.01 Hz. The system is specifically designed for electrochemical measurements, but the proposed architecture can be employed in many other fields where flexible signal generation and analysis are required. The system employs an unconventional signal generator based on two pulsewidth modulation (PWM) oscillators and an autocalibration system that allows uncertainties of less than 3% to be obtained over a range of 1 kΩ to 100 GΩ. A synchronous demodulation processing allows the noise superimposed to the low-amplitude input signals to be made negligibl

Formazione a distanza e piccole e medie imprese

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Performance Assessment of Existing Methodologies for Chemical Process Dynamic Simulation

The chemical engineer has nowadays a wide choice of tools, numerical libraries, and programming languages to perform computations. Actually, it is possible to use several well established commercial packages, implement dedicated solvers into specific programming languages, or use existing numerical libraries. Also, it is possible to combine these possibilities to get either superior performances or more robustness, according to the problem features through the so-called mixed-language approach, which is increasingly spreading in the scientific communities. Since there is no full clarity on their benefits in handling numerical problems and their performances have not been yet compared in the literature, this paper is aimed at analyzing efficiency and robustness of some of the most widespread methodologies adopted for numerical computations: the conventional methods, the implementation of numerical libraries, the mixed-language, and the commercial tools. Specifically, the common case of differential systems is selected as comparison field