GPS Safety Tracking Device: Technical Report

The scope of this particular project is to develop a device which will allow real time location tracking through a mobile application using GPS technology. Its aim is to make people’s life easier through achieving the ‘attach-and-locate’ any belongings in seconds. The location tracking is achieved by obtaining the satellites’ data using GPS technology. This is accomplished by a connection of a RaspberryPi and a GPS Module. The corresponding mobile app will constantly update the registered devices’ current location, distance between the device and the defined safety-zone, as well as the alarm status; It not only allows user to define custom ‘safety zone’ and trigger alarm when the devices enter/leave the area; and also allows remote LED/buzzer controlling through the mobile application for a safety purpose

Microstructure and mechanical behavior of in situ Ni-Ni3Si composite

Composite materials allow one to associate fragile and ductile phases in order to obtain a good combination of properties. In situ composites obtained through eutectic transformation may present a combination of phases under a condition of equilibrium. Samples of the eutectic Ni-Ni3Si alloy were arc-melted and characterized in the as cast and directionally solidified (DS) conditions. The as cast microstructure was refined and uniform, while the DS microstructure was aligned in the direction of heat extraction and presented a plane solid/liquid interface. The alloy displayed an interesting combination of relatively high strength and tensile ductility at room temperature (3.7% total strain; UTS = 8 10 MPa), and a modulus of elasticity E = 264 MPa. High temperature tests showed that the yield strength decreased almost linearly as the temperature rose. No brittle to ductile transition temperature was found. (c) 2006 Elsevier B.V. All rights reserved.4324167116717

Growth and microstructure evolution of the Nb(2)A-Al3Nb eutectic in situ composite

In situ composite materials obtained by directional growth of eutectic alloys usually show improved properties, that make them potential candidates for high temperature applications. The eutectic alloy found in the Al-Nb system is composed of the two intermetallic phases Al3Nb (D0(22)) and Nb2Al (D(8)b). This paper describes the directional solidification of an Al-Nb eutectic alloy using a Bridgman type facility at growth rates varying from 1.0 to 2.9 cm/h. Longitudinal and transverse sections of grown samples were characterized regarding the solidification microstructure by using optical and scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction. Despite both phases being intermetallic compounds, the eutectic microstructure obtained was very regular. The results obtained were discussed regarding the effect of the growth rate on the microstructure, lamellar-rod transition and variation of phase volume fraction. (c) 2004 Elsevier Inc. All rights reserved.54318719

High resolution transmission electron microscopy study of the hardening mechanism through phase separation in a beta-Ti-35Nb-7Zr-5Ta alloy for implant applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)beta-Ti alloys are highly attractive metallic materials for biomedical applications due to their high specific strength, high corrosion resistance and excellent biocompatibility, including low elastic modulus. This work aims to clarify the hardening mechanism of a beta-Ti-Nb-Zr-Ta alloy using different characterization techniques. Ingots (50 g) of Ti-35Nb-7Zr-5Ta (wt.%) alloy were arc furnace melted in an Ar((g)) atmosphere, homogenized, hot rolled, solubilized and finally aged at several temperatures from 200 to 700 degrees C for 4 h. Microstructure characterization was performed using X-ray diffraction, optical microscopy, scanning and high resolution transmission electron microscopy (HR-TEM). The 4 h aging showed that the highest hardness values were found when aged at 400 degrees C and the HR-TEM images confirmed splitting of spots on the Fourier space map, which indicated the presence of a coherent interface between separated phases (beta and beta') and explains the hardening mechanism of the alloy. Through geometric phase analysis analysis, using the HR-TEM image, the localized strain map showed 5-10 nm domains of the beta and beta' phases. The combination of suitable values of yield strength, hardness and low Young's modulus makes Ti-35Nb-7Zr-5Ta alloy suitable for medical applications as a metallic orthopedic implant. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.6416251629Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Directional solidification, microstructure and properties of the Al3Nb-Nb2Al eutectic

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The Al-Nb system exhibits a eutectic transformation at 1595.2 degrees C, which results in Al3Nb (D0(22)) and Nb2Al (D8(b)) phases. This paper is concerned with the processing of this eutectic by directional solidification. Alloys were prepared by arc melting and directionally solidified in Bridgman-type equipment. The resulting samples were utilized to evaluate the solidification microstructure and morphology regarding the growth conditions. Eutectic microstructures obtained were regular with lamellar morphology. Variations of the growth rate showed that an increase in this parameter causes a decrease in the lamellar spacing. With further increase in the growth rate, eutectic cells were observed as a result of constitutional undercooling. Oxidation tests of eutectic microstructures showed that this alloy suffers severe microstructure instability, with growth kinetics of the oxide scale of linear type. This indicates that the Al in the Nb-Al eutectic alloy is insufficient to form protective oxide films, such as, alpha-Al2O3. Finally, the heat treatment in argon atmosphere showed that the eutectic alloy presents a high degree of microstructure stability at 1200 degrees C. (C) 2004 Elsevier B. V. All rights reserved.27541671E153E158Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Effect of cooling rate on Ti-Cu eutectoid alloy microstructure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Titanium alloys present a combination of properties that makes them suitable materials for various medical applications, and there is special interest in Ti-Cu alloys for the fabrication of dental prostheses. The addition of Cu to Ti lowers the melting point of the alloy, as well as leading to the development of desirable mechanical properties. In this study a eutectoid alloy was prepared and heat treated, then cooled at various cooling rates. The eutectoid structure (alpha + Ti(2)Cu) was observed for all cooling rates used, and evidence of alpha' martensite was found for cooling rate higher than 9 degrees C s(-1). Lower cooling rates resulted in higher modulus values. This was attributed to the volume fraction of the alpha and Ti(2)Cu phases. Higher cooling rates produced structures with lower modulus values and greater hardness, a result attributed mainly to the development of a martensitic structure. (C) 2008 Elsevier B.V. All rights reserved.29310231028Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Brazilian Synchrotron Light Laboratory (LNLS)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Growth and solid/solid transformation in a Ni-Si eutectic alloy

High temperature structural components demand materials that maintain satisfactory mechanical and chemical characteristics. These needs may be met by applying some eutectic alloys, including Ni-Ni3Si. This paper deals with the directional solidification of Ni-Ni3Si grown under several growth rates. The analysis of the eutectic microstructure was carried out using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The results obtained provided a precise analysis of the Ni3Si phase. It could be noticed that the solid/solid transformations by which Ni3Si phase goes through, deeply affects its morphology. In addition, quantitative information on the eutectic structure was obtained. It was confirmed that the growth rate variation deeply affects the final microstructure as it influences the efficiency of atomic diffusion along the solid/liquid interface. (c) 2005 Elsevier B.V. All rights reserved.3994167120220

On the properties of the eutectic alloy Al(3)(Nb,Cr)+Cr(Al,Nb)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The eutectic alloy Al(3)(Nb,Cr)+Cr(Al,Nb) forms an insitu composite and the Al(3)Nb presents high specific strength and low oxidation rate that may be improved by the combination with other phases. The purpose of this work is to investigate physical, mechanical and oxidation properties of the eutectic alloy. Therefore, Rietveld analysis was carried out for furnace cooled and water quenched samples and oxidation tests were performed on directional solidified samples. Compressive tests were performed for the eutectic alloy and also for the Nb-74.8% Cr-24.6% Al alloy in the as-cast condition. The alloy presents 12.9% Cr(Al,Nb) at room temperature, retained from the transformation Cr(Al,Nb) to Al(Nb)Cr(2). The combination of Al(3)Nb with Cr(AI,Nb) and AI(Nb)Cr, considerably improves mechanical behaviour, leading the yield strength to 1525 MPa at 800 degrees C and 925 MPa at 900 degrees C. The oxidation tests showed the formation of several oxides at all temperatures studied and that from 900 degrees C on alfa Al(2)O(3) is formed both in air and O(2) except under O(2) at 1000 degrees C. It is believed that the Cr(Al,Nb) phase acts as an Al reservoir for the formation of the various Al(2)O(3) scales. (C) 2007 Elsevier B. V. All rights reserved.46441671162167Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Growth and morphological characterization of Al-Cr-Nb eutectic alloys

Directional solidification of eutectic alloys attracts considerable attention, when in situ composites are concerned. The eutectic alloys are regarded as presenting regular morphology (lamellar and fibrous structures). Besides, when directionally solidified they show high microstructure stability at high temperatures. This work reports a morphological study of an Al-Cr-Nb eutectic alloy. The solidification morphology of the alloys was studied both in the as-cast and in the directionally solidified conditions. The samples were first obtained in an arc furnace and then directionally solidified using Bridgman equipment. During the directional solidification process, the growth rates utilized varied from 5.0 to 30.0 mm/h. Optical (OM) and scanning electron microscopy (SEM) was used in order to determine the influence of the solidification conditions on the microstructure. The results obtained indicated that the eutectic transformation temperature is near 1347.9 degrees C with formation of Al-3(Nb,Cr) and Cr(AI,Nb) phases. Also, it was noted that the Cr(AI,Nb) phase undergoes a polymorphic transformation (similar to 892.3 degrees C) forming the Al(Nb)Cr-2 compound, followed by eutectoid decomposition Cr(AI,Nb) -> Al(Nb)Cr-2 + Al8Cr5. (c) 2005 Elsevier B.V. All rights reserved.4024167115616