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Silva C.P.N.,Federal University of Pernambuco | Machado G.G.,Federal University of Pernambuco | de Oliveira E.M.F.,Federal University of Pernambuco | de Oliveira M.R.T.,Federal University of Pernambuco | And 2 more authors.
Microwave and Optical Technology Letters | Year: 2017

Instantaneous frequency measurement (IFM) systems have been developed during the last decades, and new designs came across trying to keep the system as compact as possible. In this paper, the authors present compact interferometers based on Hilbert fractal geometry for a 4-bit IFM system. The interferometers operate in the range 4.66–6.38 GHz, using a Wilkinson power divider connected to two microstrip lines, which one of these is the Hilbert fractal curve. The design and simulations to be presented were done in a full wave EM simulator. Measured and simulating results are presented and compared. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1153–1157, 2017. © 2017 Wiley Periodicals, Inc.

Do Nascimento Oliveira C.A.,Federal University of Pernambuco | Gonzalez C.H.,Federal University of Pernambuco | Filho O.O.,Federal University of Pernambuco | Da Silva N.J.,Instituto Federal Of Pernambuco Ifpe | And 3 more authors.
Materials Research | Year: 2015

Shape memory alloys (SMAs) present some characteristics, which make it unique material to be use in applications that require strength and shape recovery. This alloys was been used to manufacture smart actuators for mechanical industry devices and several other applications in areas as medicine, robotics, aerospace, petroleum and gas industries. However it is important to know the actuators response to external stimulus (heat source, electrical current and/or external stress) in these technological applications. This work investigated the thermomechanical behaviors of helical actuators produced from Ti-Ni alloy commercial wires. Initially, the wire was subjected to some heat treatment and characterized by differential scanning calorimeter (DSC), scanning electron microscopy (SEM), optical microscopy (OM) and Energy dispersive spectroscopy. Then two heat treatments were selected to obtain the helical actuators. The actuators were tested in an apparatus developed to apply an external traction stress in helical actuators during thermal cycles. Two wires were tested in a dynamic mechanical analyzer (DMA). The results were analyzed in comparison with thermoplastic properties obtained in thermomechanical tests. The analysis took into consideration the wiring forming process, the precipitates formation, the stress fields generated by dislocations and reorientation of martensite variants during the actuators training process.

Silva E.M.,Instituto Federal Of Pernambuco Ifpe | Da Costa M.F.,Federal University of Pernambuco | Barletta M.,Federal University of Pernambuco
Journal of Coastal Research | Year: 2013

The monitoring of seawater physico-chemistry using automated buoys is well developed for large oceanic scales. Accessible and easy to handle small-scale monitoring buoys and land-based receivers are still missing in coastal water monitoring. River basins, reservoirs and estuaries are the most stressed aquatic environments as a result of their intensive use. These water bodies, and adjacent coastal waters, are priority candidates for continuous and reliable water quality monitoring. Environmental Agencies establish monitoring programs that involve water sampling and laboratorial analysis. Small-scale automated monitoring systems work with relatively low costs if simple materials and readily available technologies are used. We propose the development of a monitoring system that involves small plastic buoys/moorings with temperature and salinity probes, signal emitter/receptor devices, and Programmable Logic Controller (PLC) with wireless communication. The proposed technologies already exist, but need to be developed to work together in inhospitable environments as salt water and high temperatures. It is indicated for the continuous monitoring of shallow water bodies within coastal conservation units, municipal water reservoirs and even by environmental agencies in an upstream/downstream design to monitor water intake and effluents discharges from industries and water treatment plants. Private users may also be interested in installing the system if they are responsible for the maintenance of the water quality of coastal environments. Cheaper and efficient water quality monitoring is key to the building of meaningful time series that can be statistically treated to allow predictions of water quality changes. © Coastal Education & Research Foundation 2013.

Espinosa-Espinosa M.,Catalonia Technology Center of Telecomunications | Llamas-Garro I.,Catalonia Technology Center of Telecomunications | De Oliveira B.G.M.,Instituto Federal Of Pernambuco Ifpe | De Melo M.T.,Federal University of Pernambuco | Kim J.-M.,Chonbuk National University
Mediterranean Microwave Symposium | Year: 2016

This paper presents a building block approach for the design of frequency identification receivers. The devices are based on a Reconfigurable Discriminator (RD) for frequency measurement, operating from 1 to 4 GHz. The RD is a two-port device used to identify the frequency of an unknown signal. The devices use RF switches, which are implemented with PIN diodes to select different bits used for frequency identification. © 2015 IEEE.

da Silva N.V.,Instituto Federal Of Pernambuco Ifpe | Costa R.G.,Federal University of Paraiba | de Medeiros G.R.,Instituto Nacional do Semiarido INSA | de Medeiros A.N.,Instituto Federal Of Pernambuco Ifpe | And 3 more authors.
Archivos de Zootecnia | Year: 2014

It was evaluated the carcass characteristics of 40 sheeps of Santa Inês breed, uncastrated, with initial average weight of 17.41 ± 1.27 kg and average age of 120 days and slaughtered with body weight of 32 kg or 105 days of confinement. The animals were placed in individual stalls and fed with diets containing increasing levels (0, 20, 40 and 60 %) of corn replacement by guava agroindustrial by-product. It was used the lineation completely at random with four treatments and ten repetitions. It occurred a diet effect over the weight and the percentage of carcasses and retail cuts. The replacement of 60 % of corn by guava agroindustrial by-product provided smaller hot carcass weight (11.91 kg) and cold carcass (11.81 kg), lower hot carcass yield (42.08 %) and cold carcass weight (41.72 %), lower rib eye area (9.94 cm2), and muscle (0.33 g/cm), and higher content of gastrointestinal tract (7.43 kg). It is estimated that the inclusion of up to 40 % of guava agroindustrial by-product in the diet replacing the corn is relevant to attaining carcasses with characteristics appropriate to the consumer market, especially where this food resource is available.

da Silva N.V.,Instituto Federal Of Pernambuco Ifpe | Costa R.G.,Federal University of Paraiba | de Medeiros A.N.,Federal University of Paraiba | de Azevedo P.S.,Federal University of Paraiba | And 3 more authors.
Archivos de Zootecnia | Year: 2012

The objective of this study was to evaluate the use of silk flower (Calotropis procera SW) hay in 32 castrate male lambs of Morada Nova breed, in feedlot, fed with diets containing 0.0, 15.0, 30.0, and 45.0% of silk flower hay (SFH). The animals (12.72±1.99 kg BW) were slaughtered at 19.29±2.25 kg BW. A completely randomized design, with four diets and eigth replicates, was used. Increasing SFH levels reduced carcass conformation (2.31, 2.58, 2.17 and 1.81 points), leg perimeter (33.38, 32.17, 32.17, 30.00 cm), carcass compacity (live weigth/carcass length) (0.18, 0.18, 0.17, 0.15 cm), corrected half carcass weight (4.52, 4.63, 4.43, 3.69 kg), loin weight (0.66, 0.69, 0.64, 0.50 kg), shoulder weight (0.83, 0.86, 0.80, 0.67 kg) and rib weight (1.13, 1.09, 1.05, 0.84 kg), while there was a linear increase in leg weight (30.98, 30.81, 31.60, 34.47 kg) and mesenteric fat percentage (1.02, 0.65, 1.17, 1.42%). Increasing dietary levels of SFH to lambs affected carcass measurements and carcass yield, retail cuts and non-carcass components. It is thought that the inclusion of 30% of SFH in the diet is excellent for the maintenance of carcass characteristics in regions where there is access to this fodder plant.

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