On the optimum parameters of a device for harvesting energy from running and walking

This paper investigates the feasibility of using an energy harvesting device tuned such that its natural frequency coincides with higher harmonics of the input to capture energy from walking or running human motion more efficiently. The paper starts by reviewing the concept of a linear resonant generator for a tonal frequency input and then derives an expression for the power harvested for an input with several harmonics. The amount of power harvested is estimated numerically using measured data from human subjects. Assuming that the input is periodic, the signal is reconstructed using a Fourier series before being used in the simulation. It is found that although the power output depends on the input frequency, the choice of tuning the natural frequency of the device to coincide with a particular higher harmonic is restricted by the amount of damping that is needed to maximize the amount of power harvested, as well as to comply with the size limit of the device. It is also found that it is not feasible to tune the device to match the first few harmonics when the size of the device is small, because a large amount of damping is required to limit the motion of the mass.

A simple method for choosing the parameters of a two degree-of-freedom tuned vibration absorber

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental Active Vibration Control in Truss Structures Considering Uncertainties in System Parameters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of processing parameters on nanomaterials synthesis efficiency by a carbothermal reduction process

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estimative of genetic parameters in progeny test of Pinus caribaea Morelet var. hondurensis Barret & Golfari by quantitative traits and microsatellite markers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mating system parameters at hierarchical levels of fruits, individuals and populations in the Brazilian insect-pollinated tropical tree, Tabebuia roseo-alba (Bignoniaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Semen parameters, fertility and testosterone levels in male rats exposed prenatally to betamethasone

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Immunovirological parameters and cytokines in HIV infection

Enquanto modernas terapias antirretrovirais (TARV) têm resultado em menores índices de morbidade e mortalidade e na melhora visível dos parâmetros clínicos e laboratoriais em infectados pelo HIV, sabe-se que seu uso em longo prazo contribui com aparecimento dos vários eventos não associados à aids como doenças cardiovasculares, cânceres e osteoporose, comorbidades as quais têm sido propostas como algumas das mais importantes que privam a maioria dos infectados pelo vírus a apresentarem prognóstico ainda melhor. Isso ocorre porque, mesmo com diminuição da inflamação e ativação imune após intervenção medicamentosa ao paciente, tais parâmetros continuam maiores que os apresentados por indivíduos saudáveis e o desequilíbrio dos perfis de citocinas também persiste. Por isso, avaliações de outros biomarcadores na prática clínica são necessárias para complementar os exames já realizados rotineiramente e permitir o monitoramento mais eficaz dos portadores do HIV. Esta revisão tem o intuito de investigar o papel das citocinas como potenciais marcadores, relacionando estudos sobre o comportamento de várias delas em diversas fases da infecção por HIV, na presença ou não de TARV.

Respiratory Parameters and Exercise Functional Capacity in Preeclampsia

Objective: To evaluate maximal respiratory pressures, pulmonary volumes and capacities and exercise functional capacity in pregnant women with preeclampsia. Method: Primigravid women with preeclampsia and healthy primigravid women were evaluated by means of manovacuometry, spirometry and the 6-minute walk test. Results: The group with preeclampsia showed higher minute ventilation and lower forced vital capacity and exercise tolerance. The presence of preeclampsia and forced vital capacity were predictors in the six-minute walk test. Conclusion: Preeclampsia showed significant alterations in the respiratory system and was associated with lower exercise tolerance; however, it did not affect respiratory muscle functions.