ISSN: 2310-2799
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546,196 artículos
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Año:
2017
ISSN:
2525-0159
Cusato, Leslie; Estevez, Mariel; Santiago, Guillermo Daniel; González, Martín Germán
FIUBA
Resumen
In this paper we present the study of three sensors, based on piezoelectric polymer thin films, for photoacoustic systems used in the characterization of liquids. Its performance was compared by carrying out measurements on well-known liquids. From the measured data, the sensitivity, noise level and quantification limit of each of the sensors were determined. The device with the best characteristics was used in the determination of the quantum efficiency of two dyes: Rhodamine 6G and Rhodamine B. The measured values agree very well with those reported by other authors.
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Año:
2017
ISSN:
2525-0159
Messina, Francisco Javier; Rey Vega, Leonardo; Galarza, Cecilia Gabriela
FIUBA
Resumen
We first present a detailed review of two popular classes of model based synchrophasor estimators. They are the discrete Fourier transform (DFT) and the Taylor-Fourier transform (TFT) class estimators, which arise from constant or polynomial phasor models, respectively. Limitations of these techniques, arising from the models themselves, are exposed. These limitations make the original DFT and TFT approaches unfitted for situations where the phasor can not be properly described in such simple terms. This issue can be addressed with the recently introduced convex semi-infinite programming (CSIP) based estimators, which are also reviewed. In particular, we present the constraints associated with the tests which are most critical for the model based methods, showing how to precisely control the estimators performance in those cases. Finally, we show that the DFT and TFT estimators are particular instances of the CSIP estimator, so that there exists a connection between these two apparently different approaches. This opens the door for future analyses and developments.
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Año:
2017
ISSN:
2525-0159
Massaro Rocca, Patricio; Ciocci Brazzano, Ligia; Acosta, Eduardo Omar; González, Martín Germán
FIUBA
Resumen
Optoacoustic imaging is a hybrid technique with a rapid evolution within the area of biomedical imaging. It combines the rich and versatile optical contrast with the high spatial resolution associated with the low-dispersion ultrasonic wave propagation nature. Its application raises a series of difficult problems that require further developments. One of them, the objective of this work, is to analyze how the optoacoustic image reconstruction algorithms are affected by the use of non-ideal (real) broadband sensors. In particular, as an original contribution, we study the case of integrating ultrasonic sensors based on piezoelectric polymer thin films. In order to achieve this, a temporary back-projection algorithm was implemented for line detectors. Then, using a parametric model for this type of sensors, we studied the influence of the use of a real device on the efficiency of the implemented algorithm.
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Año:
2017
ISSN:
2525-0159
Rodríguez Rodríguez, José-Víctor; Rodríguez-Rodríguez, Ignacio; Serrano Martínez, José Luis
FIUBA
Resumen
In this work, a series of relatively simple experiments aimed at measuring the speed of light in different media within an educational environment is presented. In this way, the different methods and procedures -which can be carried out within university laboratories- for measuring at what velocity light propagates through air, crystal or water are described step by step. The speed of light measurement activities presented in this article represent an enjoyable and practical way of enriching the teaching of both optics and electromagnetism, get familiar with specific instrumentation such as oscilloscopes and optical transmitters/receivers or understand the science underlying fiber optics. Finally, the proposed experiments represent, in the end, an ideal example of bringing students closer to the so-called 'scientific method'.
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Año:
2017
ISSN:
2525-0159
Abadi, Betina; Ciocci Brazzano, Ligia; Sorichetti, Patricio; González, Martín Germán
FIUBA
Resumen
This paper presents the implementation and electric characterization of a broadband piezoelectric polymer sensor with linear geometry based on a thin film of polyvinylidene fluoride. The electrical impedance of the sensor was measured as a function of frequency, and it was found that the polymer was practically not altered by the sensor fabrication process. Also, the sensor frecuency response with a transimpedance amplifier was measured. Due to the high electrical capacitance of the device, a large reduction of the system broadband was found.
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Año:
2017
ISSN:
2525-0159
Arrigo, Gastón; Sorichetti, Patricio; Acosta, Eduardo Omar
FIUBA
Resumen
In this paper we present measurements that reveal changes in the frequency response of a PIN-type photodetector with the increase of the intensity of the light reaching the detector. In particular, two effects are observed at high illumination levels: the bandwidth of the detector decreases and the phase response is modified. For low intensities the bandwidth follows a power law with exponent -1 with the average current of the photodetector, but at high illumination the exponent tends to -0.5.
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Año:
2017
ISSN:
2525-0159
Fano, Walter Gustavo; Alonso, Ramiro; Quintana, Gonzalo
FIUBA
Resumen
The coils are usually used to establish a known and uniform magnetic field zone for various applications. It is important to know the area where this magnetic field is uniform with the different spatial variables x, y, z. In the area where a uniform magnetic field is generated, sensor and magnetic field probes calibrations can be made in a low frequency range. This work is dedicated to calculate and measure the magnetic field generated by Helmholtz coils and to determine the uniformity and accuracy of the magnetic field with respect to the center of symmetry of the studied system.
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Año:
2017
ISSN:
2525-0159
Anderson Ricci, Mauricio
FIUBA
Resumen
This work presents an Internet’s Topology study, based on its tomography. Our objective was on the gathering of data and their analysis, at both levels: routers and IP. To do that, we developed an Open Source tool called Magallanes, which uses PlaneLab platform for performing explorations trough nodes around the world.
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Año:
2017
ISSN:
2525-0159
Ronis, Nicolás; García Inza, Mariano
FIUBA
Resumen
An integrated Hall sensor was designed and fabricated in a 0.5μm CMOS ONC5N/F process provided by MOSIS. On it, four different Hall Plate geometries were integrated in order to analyze their sensitivity and resistance over temperature from -40°C up to 165°C. Furthermore, an amplifier and a current spinning system to remove the amplifier and Hall Plate offset were designed and placed in the same chip. The results show a better sensitivity performance in the cross-shaped Hall Plate and a linear behavior of the sensor in the range of operation tested.
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Año:
2017
ISSN:
2525-0159
Carisimo, Esteban
FIUBA
Resumen
Internet Exchange Points (IXPs) have been responsible for leading the most significant change on Internet ecosystem in the last 15 years. Despite the popularity of IXPs, a large number of countries delayed to introduce this infrastructure in their national networks. In 2013, Bolivia encouraged the creating of a national IXP, which motivated us to make the first study about an IXP in Latin America, in a country which had not deployed this infrastructure yet. However, due to the lack of vantage points of measurement projects in Bolivia, it was necessary to develop and deploy a measurement platform, which was called PladMeD, to be able to analyze the influence of the IXP. This works presents a six-month analysis about the influence of the IXP on the national network and it mainly focuses on the modifications in the interconnection as well as the quality of service.
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