Development and Automatization of a Planar Jet Wind Tunnel for the X-wire Calibration

The scope of this study is to design an automatic control system and create an automatic x-wire calibrator for a facility named Plane Air Tunnel; whose exit creates planar jet flow. The controlling power state as well as automatic speed adjustment of the inverter has been achieved. Thus, the wind tunnel can be run with respect to any desired speed and the x-wire can automatically be calibrated at that speed. To achieve that, VI programming using the LabView environment was learned, to acquire the pressure and temperature, and to calculate the velocity based on the acquisition data thanks to a pitot-static tube. Furthermore, communication with the inverter to give the commands for power on/off and speed control was also done using the LabView VI coding environment. The connection of the computer to the inverter was achieved by the proper cabling using DAQmx Analog/Digital (A/D) input/output (I/O). Moreover, the pressure profile along the streamwise direction of the plane air tunnel was studied. Pressure tappings and a multichannel pressure scanner were used to acquire the pressure values at different locations. Thanks to that, the aerodynamic efficiency of the contraction ratio was observed, and the pressure behavior was related to the velocity at the exit section. Furthermore, the control of the speed was accomplished by implementing a closed-loop PI controller on the LabView environment with and without using a pitot-static tube thanks to the pressure behavior information. The responses of the two controllers were analyzed and commented on by giving suggestions. In addition, hot wire experiments were performed to calibrate automatically and investigate the velocity profile of a turbulent planar jet. To be able to analyze the results, the physics of turbulent planar jet flow was studied. The fundamental terms, the methods used in the derivation of the equations, velocity profile, shear stress behavior, and the effect of vorticity were reviewed.

Realizzazione di un'interfaccia universale in tecnologia Bluetooth Low Energy per sensori integrati

Lo scopo dell’elaborato di tesi è la progettazione e lo sviluppo di un’applicazione per il modulo Bluetooth Low Energy (BLE) Texas Instrument CC2650 in grado di leggere le informazioni da un sensore analogico, tramite un Analog-Digital- Converter (ADC), e di scambiare i dati con uno smartphone Android in tempo reale. L’interfaccia realizzata deve essere universale, ovvero dovrà essere compatibile con sensori di diverso tipo, facilmente estensibile per l’aggiunta di un numero maggiore di periferiche di lettura e utilizzabile con un ampio numero di dispositivi.

Construction and detectors’ characterization of a new detection system for FAMU Experiment

From 2010, the Proton Radius has become one of the most interest value to determine. The first proof of not complete understanding of its internal structure was the measurement of the Lamb Shift using the muonic hydrogen, leading to a value 7σ lower. A new road so was open and the Proton Radius Puzzle epoch begun. FAMU Experiment is a project that tries to give an answer to this Puzzle implementing high precision experimental apparatus. The work of this thesis is based on the study, construction and first characterization of a new detection system. Thanks to the previous experiments and simulations, this apparatus is composed by 17 detectors positioned on a semicircular crown with the related electronic circuit. The detectors' characterization is based on the use of a LabView program controlling a digital potentiometer and on other two analog potentiometers, all three used to set the amplitude of each detector to a predefined value, around 1.2 V, set on the oscilloscope by which is possible to observe the signal. This is the requirement in order to have, in the final measurement, a single high peak given by the sum of all the signals coming from the detectors. Each signal has been acquired for almost half of an hour, but the entire circuit has been maintained active for more time to observe its capacity to work for longer periods. The principal results of this thesis are given by the spectra of 12 detectors and the corresponding values of Voltages, FWHM and Resolution. The outcomes of the acquisitions show also another expected behavior: the strong dependence of the detectors from the temperature, demonstrating that an its change causes fluctuations in the signal. In turn, these fluctuations will affect the spectrum, resulting in a shifting of the curve and a lower Resolution. On the other hand, a measurement performed in stable conditions will lead to accordance between the nominal and experimental measurements, as for the detectors 10, 11 and 12 of our system.

Crack measurements in structural concrete with D.I.C. system and validation of a tensile constitutive law

Compared with other mature engineering disciplines, fracture mechanics of concrete is still a developing field and very important for structures like bridges subject to dynamic loading. An historical point of view of what done in the field is provided and then the project is presented. The project presents an application of the Digital Image Correlation (DIC) technique for the detection of cracks at the surface of concrete prisms (500mmx100mmx100mm) subject to flexural loading conditions (Four Point Bending test). The technique provide displacement measurements of the region of interest and from this displacement field information about crack mouth opening (CMOD) are obtained and related to the applied load. The evolution of the fracture process is shown through graphs and graphical maps of the displacement at some step of the loading process. The study shows that it is possible with the DIC system to detect the appearance and evolution of cracks, even before the cracks become visually detectable.