Scielo RSS <![CDATA[Journal of applied research and technology]]> http://www.scielo.org.mx/rss.php?pid=1665-642320160004&lang=es vol. 14 num. 4 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.mx/img/en/fbpelogp.gif http://www.scielo.org.mx <![CDATA[Carbon nanotube-reinforced aluminum composite produced by induction melting]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400215&lng=es&nrm=iso&tlng=es Aluminum/carbon nanotube composite is a promising candidate material for aerospace applications owing to its high strength-to-weight ratio. Because of the low density of carbon nanotubes (CNTs), their dispersion is difficult in molten metal. We investigated induction melting, a fairly distinct approach to facilitate the dispersion of CNTs in molten aluminum. The nanocomposites were characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy and mechanical testing. Refinement in crystallite size (∼320 nm) and increase in lattice strain (∼3.24 × 10−3) were observed in the composites. A simultaneous increase in yield strength (∼77%), tensile strength (∼52%), ductility (∼44%) and hardness (∼45%) was observed. Induction melting appeared to be a potential method to fabricate aluminum-CNTs composites. <![CDATA[Influence of HCl on the NPs-CdSe synthesis prepared by the colloidal method]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400225&lng=es&nrm=iso&tlng=es Cadmium selenide nanoparticles (NPs-CdSe) were synthesized by colloidal route at room temperature and atmospheric pressure using cadmium chloride (CdCl2·2.5 hydrate) and elemental selenium (Se) as precursors. Sodium borohydride (NaBH4) was used as reducing agent to obtain Se2− ions and an aqueous solution with a NaOH and Penta sodium tripolyphosphate (STPP) was used to protect Cd2+ ions. To remove the by-products generated during the chemical reaction and to promote the precipitation of NPs-CdSe, a cleaning process with an aqueous solution of HCl was performed. The HCl volume was varied from 0.2 to 1.2 ml during the cleaning process to study its effects on CdSe synthesis. The crystalline structure was analyzed by inspection of the high-resolution transmission electron microscope (HR-TEM) and X-ray diffraction (XRD). This analysis showed that crystals of CdSe exhibit a face-centered cubic structure (FCC). The calculated crystallite size is 3.5 nm and increases to 4.5 nm as the HCl volume increases. The morphologies of the products were observed by SEM and TEM techniques. HRTEM images showed that NPs-CdSe synthetized to 0.8 ml are composed of a great number of homogeneous and smooth nanospheres which are not appreciable in SEM but are observable in TEM. By contrast, 0.2 and 1.2 ml HCl samples are comprised of a great deal of rods of compounds of Se mixed with CdSe spheres nanostructures. This work, which did not require the use of surfactants complexes or specials environment, is considered to have advantages over other works. <![CDATA[Synthesis of nanostructured metal-, semiconductor-, and metal/semiconductor-mordenite composites from geothermal waste]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400232&lng=es&nrm=iso&tlng=es Successful synthesis of metal-, semiconductor-, and metal/semiconductor-mordenite nanocomposites, using geothermal solid waste as precursor is reported. Powders of nanostructured composites, consisting of metal and/or semiconductor nanoparticles grown on a mordenite-type zeolitic matrix surface, were synthesized by a one-step solvent-free and organic template-free process. The developed methodology is capable of controlling and tuning the final properties of composites from their synthesis and is also reproducible and repeatable. For comparison and demonstration of the application of the final products, dye photocatalysis degradation tests were done using commercial TiO2 as reference (degradation reached ∼75% in 215 min, k = 0.004 min−1), [M]-S-MOR samples revealed better performance (≥95% in 100 min, k = 0.009 min−1). <![CDATA[Heating ability and hemolysis test of magnetite nanoparticles obtained by a simple co-precipitation method]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400239&lng=es&nrm=iso&tlng=es The present paper reports the heating ability and hemolysis test of magnetite nanoparticles (MNPs) for biomedical applications, obtained by a novel and easy co-precipitation method, in which it is not necessary the use of controlled atmospheres and high stirring rates. Different molar proportions of FeCl2:FeCl3 (2:1 and 3:2 respectively) were used and the obtained MNPs were analyzed by X-ray diffraction, vibrating sample magnetometry and transmission electron microscopy. The heating ability was evaluated under a magnetic field using a solid state induction heating equipment at two different frequencies (362 and 200 kHz). Additionally, a hemolysis test was performed according to the ASTM method. The obtained ferrites showed a particle size in the range of 8-12 nm and superparamagnetic behavior. The MNPs increased the temperature up to 43.1 °C in 5 min under a low magnetic field and showed non hemolytic effect up to 3 mg/ml. The MNPs obtained are highly potential materials for hyperthermia cancer treatment. <![CDATA[Development of non-contact structural health monitoring system for machine tools]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400245&lng=es&nrm=iso&tlng=es In this era of flexible manufacturing systems, a real-time structural health monitoring (SHM) is paramount for machining processes which are of great relevance today, when there is a constant call for better productivity with high quality at low price. During machining, vibrations are always brought forth because of mechanical disturbances from various sources such as an engine, a sound, and noise, among others. A SHM system provides significant economic benefits when applied to machine tools and machining processes. This study demonstrates a non contact SHM system for machine tools based on the vibration signal collected through a low-cost, microcontroller based data acquisition system. The examination tests of this developed system have been carried out on a vibration rig. The readings have also been calibrated with the accelerometer to validate the proposed system. The developed system results in quick measurement, enables reliable monitoring, and is cost effective with no need to alter the structure of the machine tool. It is expected that the system can forewarn the operator for timely based maintenance actions in addition to reducing the costs of machine downtime and acquiring equipments with reduction in complexity of machine tools. <![CDATA[A rotary electromagnetic microgenerator for energy harvesting from human motions]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400259&lng=es&nrm=iso&tlng=es In this paper, a rotary electromagnetic microgenerator is analyzed, designed and built. This microgenerator can convert human motions to electrical energy. The small size and use of a pendulum mechanism without gear are two main characteristics of the designed microgenerator. The generator can detect small vibrations and produce electrical energy. The performance of this microgenerator is evaluated by being installed peak-to-peak during normal walking. Also, the maximum harvested electrical energy during normal walking is around 416.6 μW. This power is sufficient for many applications. <![CDATA[A dedicated electric oven for characterization of thermoresistive polymer nanocomposites]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400268&lng=es&nrm=iso&tlng=es The construction, characterization and control of an electric oven dedicated to the study of thermoresistive polymer nanocomposites is presented. The oven is designed with a heating plate capable of reaching 300 °C with a resolution of 0.3 °C and an area of uniform temperature of 3.8 cm × 2.5 cm. The temperature is regulated by means of a discrete proportional-integral-derivative controller. A heat transfer model comprising three coupled non-linear differential equations is proposed to predict the thermal profiles of the oven during heating and cooling, which are experimentally verified. The oven is used for thermoresistive characterization of polymer nanocomposites manufactured from a polysulfone polymer and multiwall carbon nanotubes. <![CDATA[Lifetime modeling of silica optical fiber in static fatigue test]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400278&lng=es&nrm=iso&tlng=es Abstract During their use, optical fibers are subject to harsh installation and environmental conditions. To evaluate more precisely the lifetime of an optical fiber, it is necessary to study the mechanical behavior of optical fibers under extreme conditions, in particular under mechanical and thermal stresses. This paper presents the results of new silica optical fibers aged in hot water between 20 °C and 70 °C and subjected to mechanical static bending stresses from 3 GPa to 3.5 GPa. Thermal dependence of the time to failure was observed. This dependence can be described by the Arrhenius model, where the activation energy is one of the main physical characteristic. The stress corrosion parameter also seems to regularly change with temperature. <![CDATA[Retraction notice to "Buyer-Supplier Transport Access Measures for Industry Clusters" [JART 12 (2014) 839-849]]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1665-64232016000400286&lng=es&nrm=iso&tlng=es Abstract During their use, optical fibers are subject to harsh installation and environmental conditions. To evaluate more precisely the lifetime of an optical fiber, it is necessary to study the mechanical behavior of optical fibers under extreme conditions, in particular under mechanical and thermal stresses. This paper presents the results of new silica optical fibers aged in hot water between 20 °C and 70 °C and subjected to mechanical static bending stresses from 3 GPa to 3.5 GPa. Thermal dependence of the time to failure was observed. This dependence can be described by the Arrhenius model, where the activation energy is one of the main physical characteristic. The stress corrosion parameter also seems to regularly change with temperature.