Coupling rate measurement of a novel multi-actuated piezoelectric device using optical interferometry

The class of piezoelectric actuators considered in this paper consists of a multi-flexible structure actuated by two or more piezoceramic devices that must generate different output displacements and forces at different specified points of the domain and in different directions. The devices were modeled by finite element using the software ANSYS and the topology optimization method. The following XY actuators were build to achieve maximum displacement in the X and Y directions with a minimum crosstalk between them. The actuator prototypes are composed of an aluminum structure, manufactured by using a wire Electrical Discharge Machining, which are bonded to rectangular PZT5A piezoceramic blocks by using epoxy resin. Multi-actuator piezoelectric device displacements can be measured by using optical interferometry, since it allows dynamic measurements in the kHz range, which is of the order of the first resonance frequency of these piezomechanisms. A Michelson-type interferometer, with a He-Ne laser source, is used to measure the displacement amplitudes in nanometric range. A new optical phase demodulation technique is applied, based on the properties of the triangular waveform drive voltage applied to the XY piezoelectric nanopositioner. This is a low-phase-modulation-depth-like technique that allows the rapid interferometer auto-calibration. The measurements were performed at 100 Hz frequency, and revealed that the device is linear voltage range utilized in this work. The ratio between the generated and coupled output displacements and the drive voltages is equal to 10.97 nm/V and 1.76 nm/V, respectively, which corresponds to a 16% coupling rate. © 2010 IEEE.

Efeitos de uma pré temporada em parâmetros anaeróbios e comparação de parâmetros aeróbios e anaeróbios de futebolistas de diferentes categorias

Pós-graduação em Fisioterapia - FCT

Síntese e caracterização de copolímeros de polietilenoglicol monometil éter em quitosana cationizada para futuras aplicações em biotecnologia

Pós-graduação em Química - IQ

Utilização da percepção subjetiva de esforço para controlar a intensidade do aquecimento realizado através da corrida em crianças

The aim of this study was to verify the use of exertion subjective perception to control warm-up intensity performed by continuous running in children. Twenty-one children (11,4 ± 0,8 years, 45 ± 9,8 kg e 153,6 ± 9,6 cm), performed warm-up by continuous running in randomic order in three conditions with diferent intensities using rate of perceived exertion (RPE). The intensities were chosen according to RPE Borg CR-10 and the arbitrary units used were three (B3), Five (B5) and nine (B9). The heart rate (HR) and mean velocity of the run (VEL) were evaluated to analyse the intensity of the three warm-up conditions. Statistical analysis was done by annova one-way followed by post-hoc tukey test, considering significant level of 5%. There were significant increase in HR (B3= 112 ± 10, B5 = 140 ± 18 e B9 = 176 ± 21 bpm) and VEL (B3 = 4,01 ± 0,5, B5 = 7,09 ± 1,22 e B9 = 10,97 ± 1,70 km/h) between B5 and B9 condition compared to B3. Moreover, in both parameters B9 presented significantly higher results compared to the condition B5. It´s possible to control warm-up intensity performed by continuous running in children using RPE Borg CR-10.

Estrategias orientadoras ante la inequidad psicosocial

El presente artículo corresponde a una primera etapa del proyecto de investigación denominado: "Investigación evaluativa sobre estrategias de orientación vocacional ocupacional integral para contribuir a revertir la inequidad psicosocial" , que se está llevando a cabo en la actualidad. Se hará una síntesis de las primeras estrategias metodológicas, que incluyen la modalidad de investigación-acción. En esta primera etapa, se analizan los primeros resultados de: a) Los talleres de Información Orientada, y b) La escala de afrontamiento para adolescentes. Cada una de estas intervenciones, que apuntan a diferentes objetivos, van brindando insumos para un primer nivel de análisis. Dicha intervención permite conocer qué recursos les brinda la institución escuela a estos jóvenes para la elección de un proyecto educativo, laboral, personal y social. Se comprueba la importancia de: tener un espacio de información y reflexión compartida; analizar las distorsiones en la información; y profundizar los interrogantes que produce todo cambio. Asimismo, comprobar cómo pueden afrontar dichos jóvenes, pertenecientes a escuelas medias denominadas "vulnerables", diversas situaciones de la vida diaria. En este trabajo, se realiza un análisis comparativo con otra institución educativa de prestigio en la región, cuya población se encuentra en una mejor situación socioeconómica

Estrategias orientadoras ante la inequidad psicosocial

El presente artículo corresponde a una primera etapa del proyecto de investigación denominado: "Investigación evaluativa sobre estrategias de orientación vocacional ocupacional integral para contribuir a revertir la inequidad psicosocial" , que se está llevando a cabo en la actualidad. Se hará una síntesis de las primeras estrategias metodológicas, que incluyen la modalidad de investigación-acción. En esta primera etapa, se analizan los primeros resultados de: a) Los talleres de Información Orientada, y b) La escala de afrontamiento para adolescentes. Cada una de estas intervenciones, que apuntan a diferentes objetivos, van brindando insumos para un primer nivel de análisis. Dicha intervención permite conocer qué recursos les brinda la institución escuela a estos jóvenes para la elección de un proyecto educativo, laboral, personal y social. Se comprueba la importancia de: tener un espacio de información y reflexión compartida; analizar las distorsiones en la información; y profundizar los interrogantes que produce todo cambio. Asimismo, comprobar cómo pueden afrontar dichos jóvenes, pertenecientes a escuelas medias denominadas "vulnerables", diversas situaciones de la vida diaria. En este trabajo, se realiza un análisis comparativo con otra institución educativa de prestigio en la región, cuya población se encuentra en una mejor situación socioeconómica

Estrategias orientadoras ante la inequidad psicosocial

El presente artículo corresponde a una primera etapa del proyecto de investigación denominado: "Investigación evaluativa sobre estrategias de orientación vocacional ocupacional integral para contribuir a revertir la inequidad psicosocial" , que se está llevando a cabo en la actualidad. Se hará una síntesis de las primeras estrategias metodológicas, que incluyen la modalidad de investigación-acción. En esta primera etapa, se analizan los primeros resultados de: a) Los talleres de Información Orientada, y b) La escala de afrontamiento para adolescentes. Cada una de estas intervenciones, que apuntan a diferentes objetivos, van brindando insumos para un primer nivel de análisis. Dicha intervención permite conocer qué recursos les brinda la institución escuela a estos jóvenes para la elección de un proyecto educativo, laboral, personal y social. Se comprueba la importancia de: tener un espacio de información y reflexión compartida; analizar las distorsiones en la información; y profundizar los interrogantes que produce todo cambio. Asimismo, comprobar cómo pueden afrontar dichos jóvenes, pertenecientes a escuelas medias denominadas "vulnerables", diversas situaciones de la vida diaria. En este trabajo, se realiza un análisis comparativo con otra institución educativa de prestigio en la región, cuya población se encuentra en una mejor situación socioeconómica

Occurrence of hiatuses PH and NH 1 through NH 7 in DSDP holes

Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms. The opening of the Drake Passage in the latest Oligocene to early Miocene (25-20 Ma) resulted in the establishment of the deep circumpolar current, which led to thermal isolation of Antarctica and increased global cooling. This development was associated with a major turnover in planktic organisms, resulting in the evolution of Neogene assemblages and the eventual extinction of Paleogene assemblages. The erosive patterns of two widespread hiatuses (PH, 23.0-22.5 Ma; and NH 1, 20-18 Ma) indicate that a deep circumequatorial circulation existed at this time, characterized by a broad band of carbonate-ooze deposition. Siliceous sedimentation was restricted to the North Atlantic and a narrow band around Antarctica. A major reorganization in deep-sea sedimentation and hiatus distribution patterns occurred near the early/middle Miocene boundary, apparently resulting from changes in oceanic circulation. Beginning at this time, deep-sea erosion occurred throughout the Caribbean (hiatus NH 2, 16-15 Ma), suggesting disruption of the deep circumequatorial circulation and northward deflection of deep currents, and/or intensification of the Gulf Stream. Sediment distribution patterns changed dramatically with the sudden appearance of siliceous-ooze deposition in the marginal and east equatorial North Pacific by 16.0 to 15.5 Ma, coincident with the decline of siliceous sedimentation in the North Atlantic. This silica switch may have been caused by the introduction of Norwegian Overflow Water into the North Atlantic acting as a barrier to outcropping of silica-rich Antarctic Bottom Water. The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. Antarctic glaciation resulted in a broadening belt of siliceous-ooze deposition around Antarctica, increased siliceous sedimentation in the marginal and east equatorial North Pacific and Indian Oceans, and further northward restriction of siliceous sediments in the North Atlantic. Periodic cool climatic events were accompanied by lower eustatic sea levels and widespread deep-sea erosion at 12 to 11 Ma (NH 4), 10 to 9 Ma (NH 5), 7.5 to 6.2 Ma (NH 6), and 5.2 to 4.7 Ma (NH 7).

Chemical composition of DSDP and ODP cherts

Rare earth element (REE), major, and trace element abundances and relative fractionations in forty nodular cherts sampled by the Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) indicate that the REE composition of chert records the interplay between terrigenous sources and scavenging from the local seawater. Major and (non-REE) trace element ratios indicate that the aluminosilicate fraction within the chert is similar to NASC (North American Shale Composite), with average Pacific chert including ~7% NASC-like particles, Indian chert ~11% NASC, Atlantic chert ~17% NASC, and southern high latitude (SHL) chert 53% NASC. Using La as a proxy for sum REE, approximations of excessive La (the amount of La in excess of that supplied by the detrital aluminosilicate fraction) indicate that Pacific chert contains the greatest excessive La (85% of total La) and SHL chert the least (38% of total La). As shown by interelement associations, this excessive La is most likely an adsorbed component onto aluminosilicate and phosphatic phases. Accordingly, chert from the large Pacific Ocean, where deposition occurs relatively removed from significant terrigenous input, records a depositional REE signal dominated by adsorption of dissolved REEs from seawater. Pacific chert Ce/Ce* <<1 and normative La/Yb ~ 0.8-1, resulting from adsorption of local Ce-depleted seawater and preferential adsorption of LREEs from seawater (e.g., normative La/Yb ~0.4), which increases the normative La/Yb ratio recorded in chert. Chert from the Atlantic basin, a moderately sized ocean basin lined by passive margins and with more terrigenous input than the Pacific, records a mix of adsorptive and terrigenous REE signals, with moderately negative Ce anomalies and normative La/Yb ratios intermediate to those of the Pacific and those of terrigenous input. Chert from the SHL region is dominated by the large terrigenous input on the Antarctic passive margin, with inherited Ce/Ce* ~1 and inherited normative La/Yb values of ~1.2-1.4. Ce/Ce* does not vary with age, either throughout the entire data base or within a particular basin. Overall, Ce/Ce* does not correlate with P2O5 concentrations, even though phosphatic phases may be an important REE carrier.