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Design of a smartphone plastic optical fiber chemical sensor for hydrogen sulfide detection
No full textWe present a low-cost, handheld plastic optical fiber (POF) sensor for hydrogen sulfide (H2S) detection integrated onto a smartphone. The sensor uses smartphone flashlight as a source and camera as a pixel-based intensity detector. The POF is interconnected to the smartphone with a 3-D-printed connector on both source/detector sides. The sensing mechanism is embedded in the fiber link, making the system an all-fiber smartphone architecture. A mobile application handles data acquisition on the Android operative system. The sensor is functionalized for H2S detection through silver deposition on the POF outer surface. Experiments demonstrate the feasibility of the sensor system as the presence of H2S is successfully measured through an increase of optical losses through the POF link. This cost-effective, scalable, and compact sensor is promising for application in environmental sensing
Design and Prototyping of New CERN Collimators in the Framework of the LHC Injector Upgrade (LIU) Project and the High-Luminosity (HL-LHC) Project
No full textA general sampling-based SMPC approach to spacecraft proximity operations
No full textThis paper considers the problem of designing a control strategy for proximity operations of space systems. The considered setup is realistic, and is based on a model derived and validated on an experimental test-bed. Parametric uncertainties due to the mass variations during operations, linearization errors, and disturbances due to external space environment are simultaneously considered. The proposed control strategy is based on a novel framework for stochastic model predictive control (SMPC), extending the results based on offline sampling strategies previously developed
Deep Classifiers-Based License Plate Detection, Localization and Recognition on GPU-Powered Mobile Platform
No full textThe realization of a deep neural architecture on a mobile platform is challenging, but can open up a number of possibilities for visual analysis applications. A neural network can be realized on a mobile platform by exploiting the computational power of the embedded GPU and simplifying the flow of a neural architecture trained on the desktop workstation or a GPU server. This paper presents an embedded platform-based Italian license plate detection and recognition system using deep neural classifiers. In this work, trained parameters of a highly precise automatic license plate recognition (ALPR) system are imported and used to replicate the same neural classifiers on a Nvidia Shield K1 tablet. A CUDA-based framework is used to realize these neural networks. The flow of the trained architecture is simplified to perform the license plate recognition in real-time. Results show that the tasks of plate and character detection and localization can be performed in real-time on a mobile platform by simplifying the flow of the trained architecture. However, the accuracy of the simplified architecture would be decreased accordingly
Layer by Layer-functionalized rice husk particles: A novel and sustainable solution for particleboard production
No full textRice husk particles from agro-wastes have been treated with a Layer by Layer (LbL) deposition of polyelectrolytes and further assembled to prepare a bio-based particle board. The all polymer system employed uses a branched polyethyleneimine combined with a polyacrylic acid. The two polyelectrolytes show a super-linear growth as demonstrated by infrared spectroscopy. A schematic description of the mechanism behind the LbL deposition on rice husk particles is proposed and discussed on the basis of electron microscopy observations. The mechanical properties of the prepared LbL-joined particle boards are evaluated and related to the unique structure and intermolecular ionic interaction occurring between the assembled polyelectrolytes. Only 2 BLs allow for the preparation of a free-standing/self-supporting material. Boards assembled with 3 and 4 BL-coated particles yielded impressive storage moduli of 1.7 and 2.2 GPa, respectively, as measured by dynamic mechanical analyses performed at different temperatures and relative humidities. When tested by three points bending mechanical tests the same materials showed an elastic moduli up to 3.2 GPa and a tensile strengths up to 12 MPa. The presented results demonstrate that the LbL functionalization of agro-waste particles represents an attractive, functional and sustainable solution for the production of mechanically strong particleboards
VHF/UHF Antenna Array Measurements with a UAV-based Test Source
No full textLow-frequency arrays represent the new generation of radio astronomical facilities capable to expand the frontiers of the Universe observation from the Earth. The most important example is the Square Kilometre Array (SKA), which will become the world's largest radio telescope upon its completion in the 2020s. Several arrays and thousands of antennas operating from 50 MHz to 20 GHz will compose the SKA, producing a total collecting area of several square kilometers. Besides the outstanding performance in terms of resolution and sensitivity, the advantage of antenna arrays is the great flexibility. In fact, the signals of all the array elements can be digitally combined and treated in different ways, e.g. from only one large group to multiple smaller ones. Moreover, a digital beam-forming system controls the observation direction that can be rapidly steered across the sky. These complex instruments require advanced procedure to test their front-end electronics. In addition, the electromagnetic characterization and the array calibration are challenging tasks especially at lower frequencies. The strong interaction between the array elements, and with the surrounding environment as well, produces effects that can be difficult to predict during the design stage. Therefore, advanced in-situ measurement procedures are required to validate the facility. In the context of the Aperture Array Verification Program (AAVP) of the SKA telescope, a test-source mounted on an Unmanned Aerial Vehicle (UAV) has been conceived in Italy within a collaboration between the Institute of Electronics, Computer and Telecommunication Engineering (IEIIT) of the Italian National Research Council (CNR), the Department of Environment, Land and Infrastructure Engineering (DIATI) of the Polytechnic of Turin and the Italian National Institute for Astrophysics (INAF). In this thesis work, the concept of a UAV-based VHF/UHF far-field test-source to perform in-situ antenna array measurements has been developed into a real system that has been used in several measurement campaigns around the world on some of the SKA pathfinders. Several relevant aspects such as measurement strategies, data processing, system design, modeling, integration and test have been addressed in great detail. A detailed data analysis has been performed after all the above mentioned campaigns. The obtained results demonstrate that the UAV-system provides good accuracy and effectiveness to characterize the radiation pattern and the polarization properties of the single antennas, the embedded elements and the whole array. The provided data are already being used by the radio astronomical scientific community to improve both the data set of the existing telescopes and the design of the new ones. The UAV has been also used as calibration source for the digital beam-forming system, providing a direct solution with a higher signal-to-noise ratio with respect to the exploitation of astronomical sources. The versatility and the transportability of the system open up a wide variety of possibilities for antenna measurement in many other applications
Modeling and Experiments of a Passive Decay Heat Removal System for Advanced Nuclear Reactors
No full textWithin the field of research and development of innovative nuclear reactors, in particular Generation IV reactors and Small Modular Reactors (SMR), the design and the improvement of safety systems play a crucial role. Among all the safety systems high attention is dedicated to passive systems that do not need external energy to operate, with a very high reliability also in the case of station blackout, and which are largely used in evolutionary technology reactors. The aim of this work is the experimental and numerical analysis of a passive system that operates in natural circulation in order to study the mechanism and the efficiency of heat removal. The final goal is the development of a methodology that can be used to study this class of systems and to assess the thermal-hydraulic code RELAP5 for these specific applications. Starting from a commercial size system, which is the decay heat removal system of the experimental lead cooled reactor ALFRED, an experimental facility has been designed, built and tested with the aim of studying natural circulation in passive systems for nuclear applications. The facility has been simulated and optimized using the thermal-hydraulic code RELAP5-3D. During the experimental tests, temperatures and pressures are measured and the experimental results are compared with the ones predicted by the code. The results show that the system operates effectively, removing the given thermal power. The code can predict well the experimental results but high attention must be dedicated to the modeling of components where non-condensable gases are present (condenser pool and surrounding ambient). This facility will be also used to validate the scaling laws among systems that operate in natural circulation
