2013
Authors
Rocha, JG; Correia, VMG; Martins, MS; Cabral, JM;
Publication
Open Biomedical Engineering Journal
Abstract
This article describes a complete prototype system that can be used in electrotherapy treatments, that is, in medical treatments involving electric currents. The system is composed of two main blocks: the master and the slave. The Master block, whose main component is a CPU, controls the user interface. The Slave block, which is composed of a microcontroller and a wave generator, produces the appropriated voltages and currents compatible with the desired treatment. The whole system is powered by a 12 V power supply and the output signal voltage ranges between -100 V and 100 V. Despite the prototype being able of performing all the electrotherapy treatments in the low-medium frequency ranges, it was tested in aesthetic mesotherapy, namely in anticellulite, located anticellulite, antistretch, and antiflaccidity. In these treatments, the output signal is composed of an overlap of two frequencies: the first one is selected in the range of 1.2 kHz - 1.8 kHz and the second in the range of 0.07 Hz - 2 Hz. The system was tested in a clinical environment with real patients. It showed good results both in effectiveness of treatments and in terms of pain suffered by the patients. © Rocha et al.
2013
Authors
Correia, V; Sencadas, V; Martins, MS; Ribeiro, C; Alpuim, P; Rocha, JG; Morales, I; Atienza, C; Lanceros Mendez, S;
Publication
SENSORS AND ACTUATORS A-PHYSICAL
Abstract
The success of artificial prosthetic replacements depends on the fixation of the artificial prosthetic component after being implanted in the thighbone. This work shows a smart prosthesis based on highly sensitive silicon thin-film piezoresistive sensors attached to a hip prosthesis. The performance of the sensors for this application is studied and compared to commercial strain gauge sensors. Mechanical stress-strain experiments were performed in compressive mode, during 10,000 cycles and data was acquired at mechanical vibration frequencies of 0.5 Hz, I Hz and 5 Hz, and sent to a computer by means of a wireless link. The results show that there is a decrease in sensitivity of the thin-film silicon piezoresistive (n-type nanocrystalline Si) sensors when they are attached to the prosthesis, however this decrease does not compromise its monitoring performance. The sensitivity, compared to that of commercial strain gauges, is much larger due to their higher gauge factor (-23.5), when compared to the gage factor of commercial sensors (2).
2013
Authors
Beier, C; Mata, J; Stockhert, F; Mattielli, N; Brandl, PA; Madureira, P; Genske, FS; Martins, S; Madeira, J; Haase, KM;
Publication
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
Abstract
The islands of the Azores archipelago emerge from an oceanic plateau built on lithosphere increasing in age with distance from the Mid-Atlantic Ridge from 10 to 45 Ma. Here, we present the first comprehensive major and trace element and Sr-Nd-Pb isotope data from Santa Maria, the easternmost island of the archipelago, along with published data from the other Azores islands situated much closer to the Mid-Atlantic Ridge axis. We can show that the distinctively more variable and more enriched trace element ratios at Santa Maria combined with a relatively small range in Sr-Nd-Pb isotope ratios are the result of low degrees of partial melting of a common Azores mantle plume source underneath thicker lithosphere. This implies that melt extraction processes and melting dynamics may be able to better preserve the trace element mantle source variability underneath thicker lithosphere. These conclusions may apply widely for oceanic melts erupted on relatively thick lithosphere. In addition, lower Ti/Sm and K/La ratios and SiO2 contents of Santa Maria lavas imply melting of a carbonated peridotite source. Mixing of variable portions of deep small-degree carbonated peridotite melts and shallow volatile-free garnet peridotite could explain the geochemical variability underneath Santa Maria in agreement with the volatile-rich nature of the Azores mantle source. However, Santa Maria is the Azores island where the CO2-rich nature of the mantle source is more evident, reflecting a combination of a smaller extent of partial melting and the positioning at the edge of the tilted Azores mantle plume.
2013
Authors
Hildenbrand, A; Marques, FO; Costa, ACG; Sibrant, ALR; Silva, PF; Henry, B; Miranda, JM; Madureira, P;
Publication
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
Abstract
Reply to the comment by Quartau and Mitchell on “Reconstructing the architectural
evolution of volcanic islands from combined K/Ar, morphologic, tectonic, and
magnetic data: The Faial Island example (Azores)”,
J. Volcanol. Geotherm. Res. 241–242, 39–48, by Hildenbrand et al. (2012)
2013
Authors
Adam, C; Madureira, P; Miranda, JM; Lourenco, N; Yoshida, M; Fitzenz, D;
Publication
EARTH AND PLANETARY SCIENCE LETTERS
Abstract
Situated in the middle of the Atlantic Ocean, the Azores plateau is a region of elevated topography encompassing the triple junction between the Eurasian, Nubian and North American plates. The plateau is crossed by the Mid-Atlantic Ridge, and the Terceira Rift is generally thought of as its northern boundary. The origin of the plateau and of the Terceira Rift is still under debate. This region is associated with active volcanism. Geophysical data describe complex tectonic and seismic patterns. The mantle under this region is characterized by anomalously slow seismic velocities. However, this mantle structure has not yet been used to quantitatively assess the influence of the mantle dynamics on the surface tectonics. In this study, we use a highly resolved tomography model to model the convection occurring in the mantle beneath the Azores region. The convection pattern points out two distinct upwelling, thus proving that the volcanism emplacement is created by a buoyant mantle upwelling. The modeled dynamic topography recovers well the characteristics of the depth anomaly associated with the Azores plateau, except for the south-eastern most part, thus proving that most of the depth anomaly associated with the Azores plateau is created by the present-day mantle dynamics. The stresses induced by the mantle convection can account for the lifting regime observed over the Azores plateau and the Terceira Rift, and its consequences in terms of surface morphology and seismicity.
2012
Authors
Cardoso, JMP; Teixeira, J; Alves, JC; Nobre, R; Diniz, PC; Coutinho, JGF; Luk, W;
Publication
2012 IEEE 20TH ANNUAL INTERNATIONAL SYMPOSIUM ON FIELD-PROGRAMMABLE CUSTOM COMPUTING MACHINES (FCCM)
Abstract
The development of applications for high-performance Field Programmable Gate Array (FPGA) based embedded systems is a long and error-prone process. Typically, developers need to be deeply involved in all the stages of the translation and optimization of an application described in a high-level programming language to a lower-level design description to ensure the solution meets the required functionality and performance. This paper describes the use of a novel aspect-oriented hardware/software design approach for FPGA-based embedded platforms. The design-flow uses LARA, a domain-specific aspect-oriented programming language designed to capture high-level specifications of compilation and mapping strategies, including sequences of data/computation transformations and optimizations. With LARA, developers are able to guide a design-flow to partition and map an application between hardware and software components. We illustrate the use of LARA on two complex real-life applications using high-level compilation and synthesis strategies for achieving complete hardware/software implementations with speedups of 2.5x and 6.8x over software-only implementations. By allowing developers to maintain a single application source code, this approach promotes developer productivity as well as code and performance portability.
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